







Calculating the area (acreage) of a four sided lot 
20070718 

From A property owner: I have a real estate property and the lot size is something I need to find out. I know the lengths of the four sides, but it isn't a rectangle, it is an odd shape. How do I find the acreage? Answered by Stephen La Rocque. 





Lot size / acreage (more than three sides) 
20070511 

From Martha: What is the lot size of the following dimensions equivalent to acre.
141.85 x 52.55 x 217.63 x 38.89 x 68.08 Answered by Penny Nom and Stephen La Rocque. 





A triangular garden 
20200524 

From yoonji: the 3 sides of a triangular garden measure 200 ft., 250 ft., and 300 ft., respectively. the garden is to be divided by a line bisecting the longest side and drawn from the opposite vertex. what is the length of the bisecting line? Answered by Penny Nom. 





An angle i a triangle 
20200516 

From Ogunjobi: Two goal post are 8m apart a footballer is 34 m from one post and 38m from the other within what angle must he kick the ball if he is to score Answered by Penny Nom. 





Running in opposite directions around a circular track 
20200511 

From Alessandra: 2. Alan and Brian are two runners. Alan runs at 6.6 m/s and Brian runs at 8.4 m/s. They start from
the same place on a circular 400 m track and run in opposite directions round and round the
track.
(a) How far has Brian run when they pass each other for the first time?
(b) After they pass each other for the second time, how much further does Brian need to run
in order to complete two laps (800 m)? Answered by Penny Nom. 





A system of equations. 
20200427 

From solomon: xy + x =28
x + y +4 Answered by Penny Nom. 





The missing diameter of a truncated cone 
20200417 

From Brandon: Need a formula to find missing large Dia of a truncated cone where the small dia =.19" Height= 2" and taper =16deg Answered by Harley Weston. 





A hemisphere and a cylinder 
20200323 

From Monalizsha: Wat is the volume and the surface area of the hemisphere and cylinder (both are together)
The height is 12cm of the cylinder and the diameter is 6cm Answered by Penny Nom. 





The side length of a hexagon 
20200205 

From Rob: I have a hexagon that is 8 feet wide how long would the sides be? Answered by Penny Nom. 





A system of inequalities 
20200201 

From Isaac: Austin has x nickels and y dimes, having a maximum of 15 coins worth a minimum of $1 combined. No more than 4 of the coins are nickels and no less than 11 of the coins are dimes. Solve this system of inequalities graphically and determine one possible solution. Answered by Penny Nom. 





Filling a 48 cubic meter tank 
20200119 

From kamohelo: An empty tank for storing water from a borehole has a volume of 480m3 if it is filled by a pump that pump water at a rate of 16L/s how many hours will it take the pump to fill this tank Answered by Penny Nom. 





What do you call a 43sided polygon? 
20200106 

From Alniko: What do you call a 43sided polygon and what is its interior angle's total measure? Answered by Penny Nom. 





Sigma notation 
20191204 

From Kenneth:
What would be used for the top and bottom indices for the sigma sign in my example shown below?
If the amounts were 1 + 2 + 3, the top index would be 3 and the bottom would be i = 1, but if the amounts are 1 + 2 + 4, or 1 + 0.05 + 1/3, what would the indices be since these amounts are in an uneven pattern.
I thank you for your reply and explanation Answered by Harley Weston. 





A hexagonal planter 
20191119 

From Colleen: I need to build a hexagon planter around a 32 square box. How long is each side of the hexagon? Answered by Penny Nom. 





Increasing your average mark 
20191101 

From Elena: After 9 weeks Mikayla has an average ark of 5 out of 10 in the weekly spelling tests. What is the minimum number of extra weeks now required to raise her average to 7? Answered by Penny Nom. 





Simultaneous equations 
20191016 

From deepak: This is too complicated please help me
8/x  10/y = 1 and x+y=9 Answered by Penny Nom. 





400 in 7.5 billion 
20190828 

From Emma: What is a better way to express 400 in 7.5 billion?
My daughter has a rare condition, I want to know the answer to say she is 1 in a ... Answered by Penny Nom. 





Six digit numbers from 4 digits 
20190730 

From Tab: How many six digit combinations can be made from the numbers zero, two, five, eight? With repetition of numbers Answered by Penny Nom. 





Price per square meter to price per square inch 
20190709 

From Al: If something costs $2.5 square meter, how much would it cost in square inches? How do i convert costs per square inch, into square meters? Answered by Harley Weston. 





How many cubes are in a 3x3x3 cube? 
20190624 

From Darren: Dear Sir/Madam,
How many cubes of different sizes (eg. 1x1x1, 2x2x2, 3x3x3) are there in total in say,
a 3x3x3 cube? I have trouble figuring this out.
Yours faithfully,
Darren Answered by Penny Nom. 





Yards, feet and gallons 
20190612 

From Ralph: How many gallons of water in a 10 yard by 10 yard container 2 1/2 feet deep? Answered by Penny Nom. 





Conversions, feet, kilometers and acres 
20190610 

From Erika: A lake has 113 feet deep and an area of 115 acres, what is the volume of the lake in cubic kilometer? Answered by Harley Weston. 





A repeating decimal divided by a whole number 
20190501 

From Emily: How do you divide repeating decimals by whole numbers? Answered by Penny Nom. 





(3d) Whether line segment intersects triangle 
20190413 

From rj: Well hello,
Lets say I have a triangle,
Not any ordinary triangle, but a triangle that is represented in 3 dimensions. I also have a line segment.
Lets say that this triangle has points A(0,0,0), B(1,0,0), C(0,1,1)
And the line segment has points D(0,1/2,0), E(1,1/2,1)
In what way can I find if the line segment and triangle intersect? Their intersection point?
I don't prefer matrices, because they don't make any sense, but ... if that's the only way to solve this, then do what's necessary.
Thank you in advance. Answered by Penny Nom. 





The area of a lot 
20190406 

From Robert: Can you help me determine the rough square footage of this lot please(attached)? I think it is nearly 7000 square feet. I am sure I need the degrees of of the corners but I dont have that. An estimate would be all I need.
Thank you for you help.
Rob Answered by Harley Weston. 





Salary Plus Commission 
20190405 

From Herschel: Fire Fighting Equipment pays salespeople as follows: $452 per week plus a commission of .9% on sales between $15,000 and $25000, with 1.1% paid on sales in excess of $25,000. Find the gross earnings for an salesperson whose Total Sales are $28,400. (No commission is paid on the first $15,000 of sales) Answered by Penny Nom. 





Four consecutive positive integers 
20190312 

From Nabila: The product of four consecutive positive integers in 24024
What is their sum? Answered by Penny Nom. 





Converting a base six number to base three 
20190310 

From Nina: Change 253 in base 6 to a number in base 3 Answered by Penny Nom. 





Random assignments 
20190302 

From Ninoshka: Liu and Michi plan to sign up for a drawing class next term.
Drawing is offered during the first 4 periods of the day, and students are assigned randomly to class.
What is the probability that Liu and Michi will have drawing together? Answered by Penny Nom. 





Running around a circular track in opposite directions 
20190224 

From carmi: how many times will lita and rose pass each other in 15 minutes if lita and rose start jogging on a 110 meters circular track. they begin at the same point but in opposite direction. lita at 8/3 meters per second and rose at 7/3 meters per second. Answered by Penny Nom. 





Composition of functions 
20190224 

From Joshua: Let g(x)=(x)^(2)+x1
Find such a function f such that
(fog)(x)=(x)^(4)+2(x)^(3)3(x)^(2)4x+6 Answered by p. 





The Polynomial Remainder Theorem 
20190223 

From pasandi: f(x) is a quadratic polynomial. when f(x) is divided by
(x1),(x2) & (x+2) the remainders respectively are 1, 4 and 2 how to find the f(x) in a question like this? Answered by Penny Nom. 





An arithmetic sequence 
20190223 

From Dalal: If x+1 and x+17 are the second and sixth term of a sequence with a common difference of 5, what's the value of x. Answered by Penny Nom. 





Margin with commission as part of selling price 
20190213 

From Anni: I need to find selling price to put us at 24% margin.
15% commission is based on selling price and is included in our cost.
I'm trying to do it excel and keep getting a circular reference.
Total cost= cost + commission (15% of selling price)
Selling price=total cost + 24% margin Answered by Penny Nom. 





Fractions with roots 
20190206 

From DEBMALYA: 5/√2+√3 1/√2√3 Answered by Penny Nom. 





An arithmetic sequence 
20190131 

From sara: if the 6th term of an arithmetic sequence is 8 and the 11th term is 2, what is the first term? Answered by Penny Nom. 





One quarter of a quarter cake 
20190130 

From Tre: 1/4 of a birthday cake was left over from a party. The next day, it is shared among 4 people. How big a piece of the original cake did each person get? Answered by Penny Nom. 





The sum of three consecutive even integers 
20190127 

From Pauleen: Translate this into algebraic expression
The sum of three consecutive even integers, if x is the first even integer Answered by Penny Nom. 





(2018^2019)(2019^2018) 
20190123 

From Nazrul: Find the remainder when (2018^2019)(2019^2018) is divided by 4? Please show me the process. Answered by Harley Weston. 





A triangle made from 12 matchsticks 
20190120 

From Palesa: How many different types of triangles can be made with a perimeter of 12 matches? Answered by Penny Nom. 





7 spheres on a hexagonal tray 
20190114 

From herm: what is the length of each side of a hexagonal tray, with the height of each side 0.75 inch, to hold seven spheres, each with a diameter of 3.00 inches? The spheres are placed such that each side of the hexagon is touched by one sphere at its midpoint (and the seventh sphere is place in the center of the "ring" of the other six spheres. Answered by Harley Weston. 





A binomial expansion 
20190105 

From shifali: if the binomial expansion of (mnx)^3 is 1+9x+ find the values of m & n Answered by Penny Nom. 





A quadrilateral inside a square 
20190102 

From Swetha: In 2*2 square ABCD, E is the mid point of the side AD. F is a
point in BE.CF is perpendicular to BE. Find the area of the quadrilateral CDEF Answered by Penny Nom. 





Solve for x in Y=1.5x + log (1+x) 
20181223 

From Asadollah: Please restate below expression in terms of y
Y=1.5x + log (1+x)
Thanks Answered by Penny Nom. 





Ten games with two possible outcomes for each game 
20181222 

From Jin: I'm trying to make a list to view all the possibility.
An example is if I have 2 games there's two outcomes (home/away)
I will use number to represent the teams.
01,23
All possible out comes are 02,03,12,13 right?
MY QUESTION If I have 10 games each have 2 outcomes (home/away) to win
What is all possible outcome.
01,23,45,67,89,1011,1213,1415,1617,1819
Could u please provide me with a list of all possible out comes
Thanks you Answered by Penny Nom. 





Simultaneous equations with fractions 
20181214 

From zaheer: solve simultaneous equations and give answer in fractional form
3x  2 = 4y +5/3
y + 7 = 2x + 4
would really appreciate some help on this please Answered by Penny Nom. 





Divisibility by 3 
20181120 

From Ray: There is a rule that a number is divisible by 3 if the sum of its digits are divisible by 3 (for example, 81=8+1=9 {divisible by 3} and 33=3+3=6 {again, divisible by 3}) I know this works but I don't know why! Please help. Answered by Penny Nom. 





Dividing by a fraction 
20181102 

From Fadely: If 8 divided by 4/2 can be expressed as 8 X 2/4, how can 8 X 2/4 be converted back to 8 divided by 4/2? Answered by Penny Nom. 





The area of a trapezoid 
20180924 

From An other: AB272 feet: AC 690 feet; CD330 Feet; DA669Feet Calculate the area in feet and Acres. Answered by Penny Nom. 





Splitting a commission 
20180913 

From Beth: If Sales Prices is $170975 and commission is 6% but listing agent gets 60% of the 6% and selling agent gens 40% of the 6% what is the actual percentage that each would actually receive? Answered by Penny Nom. 





A 3500 acre ranch 
20180830 

From Dee: I am in the middle of writing the description of the size of a ranch in my story.
It is 3500 acres. How does that equate into mileage? The main ranch house is
at one end, and the foreman's ranch house at the other end. Answered by Penny Nom. 





Two spinners 
20180813 

From Atina: A spinner has four equal sectors and a number is written on each sector; 1, 2, 3 and 4. A twodigit number is formed by spinning two times. The number on the first spinning makes the first digit and the number on the second spinning makes the second digit. For example, 2 on the first spinning and 1 on the second spinning make the number 21.
(a) Give the sample space S for the experiment.
(b) Consider the following events : E = odd number; F = number smaller than 35; G = prime number.
Give the subset of outcomes in S that defines each of the events E, F, and G.
(c) Describe the following events in terms of E, F, and G and find the probabilities for the events.
getting an even integer less than 35.
getting an odd number or an prime.
getting an even number greater than or equal to 35 that is a prime number. an odd number smaller than 35 that is not a prime number.
(d) Are E and F mutually exclusive events? Give a reason for your answer. Answered by Penny Nom. 





Linear feet and cubic feet 
20180716 

From Dave: How do I convert: 1 foot wide x 15 inches high x 19 inches deep
We are trying to figure out how to convert the linear footage into cubic footage
the above are the figures represent just 1 linear feet of several thousand
Any thing helps,
Thanks in advance
Dave Answered by Penny Nom. 





The domain of f(g(x)) 
20180618 

From Joshua: What are the restrictions of the domain of f(g(x))? Answered by Penny Nom. 





The inverse square law 
20180605 

From Amy:
Question about inverse square law ;
Hi, I'm trying to understand some nuances about this law and
have been reading about it a lot online and trying out some homework
for personal interest (hobby )  not school related.
I understand that the simple formula is ; 1/d^2
I was wondering about what appears to be an oddity to me, that
I came across when I was working with a test example I found at this
link ;
http://www.softschools.com/formulas/physics/inverse_square_law_formula/82/
The problem that caught my interest was this one on that page ;
"1) If a bright flashlight has a light intensity of 15.0 candela at a distance 1.00 m from the lens, what is the intensity of the flashlight 100.0 m from the lens?"
So I have a few different questions about this, but the most important
one is, what does it mean if we replace the "1" in ; 1/d^2 with a different value such as a ratio in the form of a decimal value, so instead we have something like this ;
0.75/d^2
???
Does this ratio represent a curve then?
I am thinking that the "1" in the normal formula represents a straight line
Some of the links I was researching ;
http://wisptools.net/book.php?c=3&s=2
http://www.softschools.com/formulas/physics/inverse_square_law_formula/82/
https://www.ndeed.org/GeneralResources/Formula/RTFormula/InverseSquare/InverseSquareLaw.htm Answered by Penny Nom. 





Monthly Pension 
20180528 

From Kenneth:
Hello:
I have a question regarding how the units cancel in the following:
A company uses the following calculation to determine the monthly payment for its employees as they retire:
1.1% * average 5 years highest salary * years of service
If an employee worked 33 years and his average 5 year salary is $30,705.17, what is his monthly payment?
I used the following to determine his monthly payment, but I am not sure how the units cancel especially the years.
1.1% * $30,705.17 * 33 years divided by 12 months/year
I determined his payment as $928.83 per month, but the year units do not cancel unless the 1.1% is per year.
Is the correct calculation 1.1%/year * $30,705.17 * 33 years divided by 12 months/year so that the units cancel properly?
The $\$30,705.17$ is an average for 5 years of working. It is not $30,705.17 per year.
I thank you for your assistance. Answered by Penny Nom. 





What is the diameter of the observable universe? 
20180527 

From peter: The diameter of the observable universe is calculated to be 92 billion light years. What would that distance be in miles given a light year is 6 trillion miles? Answered by Penny Nom. 





Making a cylinder from a metal plate 
20180518 

From Rahul: I want to make a cylinder which inside diameter is 600mm and thickness is 5mm and height is 800mm...so my question is that how much plate I need to make this happen Answered by Penny Nom. 





mg to ml 
20180517 

From Carolynne: I need to convert 12 mg to ml
density is 12.5mg/5ml
I can give dose of 1mg per pound . My dropper is in ml.
How much in ml can I give Answered by Penny Nom. 





Two expressions for the perimeter of a a rectangle 
20180513 

From Slayde: A rectangular house has one side 4 metres longer than the other. Create two different expressions for its perimeter. The expressions should be given in factorised and expanded form. Answered by Penny Nom. 





More on the curvature of the Earth 
20180423 

From will: the formula for figuring the earth's curve goes against logic, looking at a fixed point and backup 1mi. the point drops 8" then 16" in the next mi. and 32" in the third mi. why shouldn't it be 24" why is the 8" per mi. squared can you tell me in laymens terms why this is it goes against logic it would seem the correct wat would be to add up 8" per mile as you back up from the fixed point 8" 16" 24" 32" not 8/16/32/64" Answered by Harley Weston. 





The sides of a circle 
20180410 

From Reid: Hello,
I recently was wondering about whether or not a circle has an infinite number of sides, and I ended up searching it on your website. I saw that you guys found the question to be too ambiguous or something of that nature, and I thought about your process of reasoning involving vertices and such. I soon realized that I may have come up with the solution to the question, but I want to confirm it with you guys. Allow me to explain:
A circle, unlike any other typical 2 dimensional polygon, can sustain an infinite number of straight lines coming in contact with only one point on it. A square, for example, cannot. A square only has 4 locations that can sustain a such a line, each of those being its corners. The flat edge of a square cannot support a tangential line, because the line would either be crossing the edge of the square or coming into contact with multiple points along its edge.
This concept is consistent in every 2 dimensional polygon: pentagons sustain 5 locations for tangential lines, hexagons 6, nonagons 9, etc.
The reason a circle has an infinite number of sides is simply the fact that it must have an infinite number of "corners", assuming it can be defined as a polygon like any of the shapes I described above.
Corners can only exist assuming there is two sides coming into contact with one another.
If there is an infinite number of corners in the circle, which is apparent due to the above reasoning, there must be an infinite number of sides coming into contact with each other.
Thus, a circle is a polygon that consists of an infinite number of sides coming into contact with each other.
Please review this reasoning and let me know if it is solid.
Thank you! Answered by Penny Nom. 





A side of a square 
20180406 

From Angie: I am dyslexic and have problems with spelling and math I'm trying to figure 4.610 Acres Square trying to figure out how many feet or yards of one side if that makes sense to you thank you I'd really appreciate the help Answered by Penny Nom. 





Base 6 to base 4 
20180325 

From Malik: Hi Sir..!
I just want to know the proper example with a brief explanation of conversion of base 6 into base 4.
kindly reply me as soon as possible..
Thank you Answered by Penny Nom. 





Solve sinX=0.703X for X 
20180313 

From PARAM: sinX=0.703X Answered by Penny Nom. 





0.366 x cos square (02 degree 17 mins 27 seconds) 
20180312 

From michael: what is 0.366 x cos square (02 degree 17 mins 27 seconds)
what is 0.366 x cos square (88 degree 26 mins 45 seconds) Answered by Penny Nom. 





The dimensions of a rectangle 
20180303 

From Mia: A wire of length 36cm is bent to form a rectangle.
Find the dimensions of the rectangle. Answered by Penny Nom. 





nC0 + nC1 + nC2 + .... + nCn = 2^n 
20180219 

From bristal: (QQ) Prove, nC0 + nC1 + nC2 + .... + nCn = 2^n. Answered by Penny Nom. 





A footballer angle 
20180214 

From Kim: Two goal posts are 8m apart. A footballer is 34m from one post and 38m from the other. Within what angle must he kick the ball if he is to score a goal. Answered by Penny Nom. 





Related rates 
20180211 

From angelo: hi admin please help me answer this question. thank you!
At a certain instant of time, the angle A of a triangle ABC is 60 degrees and increasing at the rate of 5degrees per second, the side AB is 10cm and increasing at the rate of 1cm per second, and side AC is 16cm and decreasing at the rate of 1/2 cm per second. Find the rate of change of side AB? Answered by Penny Nom. 





Similar rectangles 
20180131 

From Kathy: A rectangular picture frame is 14 inches long and 4 inches wide. Which dimensions could a similar picture frame have.
8 L X 21 W
35 L X 15 W
49 L X 14 W
7 L X 3 W Answered by Penny Nom. 





Positive and negative values of a function 
20180130 

From Grayson: f(x)=x^6x^4
Interval: ( negative infinity, negative one )
Test Value: negative two
Function Value f(x): positive forty eight
Interval: ( negative one, zero )
Test Value: negative one
Function Value f(x): zero
Interval: ( zero, positive one )
Test Value: positive one
Function Value f(x): zero
Interval: ( positive one, positive infinity )
Test Value: positive two
Function Value f(x): positive forty eight
What is the sign of f(x) for each Interval? Answered by Penny Nom. 





Simplify 1/2^i 
20180128 

From Deepak: How do I simplify this complex equation:
z=1/(2^i) Answered by Penny Nom. 





y as an expression in terms of x 
20180120 

From Mark: What is y as an expression in terms of x ? Answered by pennt. 





The mass of a length of tree trunk 
20171113 

From SM: What is the mass of a length of 1m of trunk a tree trunk of uniform cross section of area 0.5 sq.m is made of wood of relative density 0.8? Answered by Penny Nom. 





f(x)=x^26x find f(x2) 
20171027 

From Kenneth: f(x)=x^26x find f(x2) Answered by Penny Nom. 





Salary plus commission 
20171016 

From Natasha: Veronika works at Future Shop and earns ₱10.50/h plus 6% commission on sales. Last week Veronika worked 40 hours. What was Veronikas weekly gross salary if her total sales were ₱2050? Answered by Penny Nom. 





27000001 
20171009 

From Tulashiram: If aΧ b =27000001, then what is the value of a & b ? Answered by Penny Nom. 





The square root of 6 is irrational 
20171002 

From John: http://mathcentral.uregina.ca/QQ/database/QQ.09.06/sylvia1.html
In the initial assumption of that proof, root 6 is assumed to be a/b where a and b have no common factors, but why does having a common factor make it irrational? Answered by Penny Nom. 





How many guests were present? 
20170917 

From SM: How many guests were present at an Italian dinner if every 2 guests shared a bowl of salad, every 3 guests shared a bowl of pasta, and every four guests shared a bowl of meatballs, and there were 65 bowls used altogether? Answered by Penny Nom. 





An impossible problem 
20170915 

From Fay: Given math homework problem of: Gary and Larry given 2 numbers and told to add together. Gary subtracted and got 14. Larry multiplied and got 799. I tried substitution:
XY=14 and X x Y=799
X= Y+14
(Y+14) Y=799 and here I'm stuck at Y squared+14 Y= 799
using substitution I got 47x17=799 but not 14b when subtracted. HELP????? Answered by Penny Nom. 





Simultaneous equations with fractions 
20170909 

From Farah: Hi, my name is Farah. I hope you can help me with this question . X/2 + g/5= 3 and 2g  f = 10 Answered by Penny Nom. 





Simultaneous equations 
20170902 

From keto: xy=2,x^2+xy=12 Answered by Penny Nom. 





A 4 sided lot 
20170815 

From Micheal: If one side of .4 acre is 25 feet what would the other three sides be Answered by Penny Nom. 





Significant digits 
20170806 

From Pat: The directions for a problem are: "Solve the problem, expressing your answer
using the correct number of significant figures."
Problem
0.0043 divided by 2.04
Answer before using the correct number of significant figures is
0.002107843
Is the correct number of significant figures the number below?
2107843
Pat Answered by Penny Nom. 





Long division with decimals 
20170616 

From Kenneth: Hello:
Why is it recommended to move the decimal from a divisor when dividing so that the divisor is a whole number?
I know how to divide by moving the decimal from the divisor, but I cannot explain the reason.
I thank you for your reply. Answered by Penny Nom. 





Solve the equation completely cos 2x = 1 
20170608 

From Lava: Solve the equation completely cos 2x = 1 Answered by Penny Nom. 





Simultaneous equations with fractions 
20170602 

From Jamal: 1/x + 1/y =5 and 1/y  1/x =1 Answered by Penny Nom. 





Yards per second to miles per hour 
20170511 

From Scott: If a soccer ball travels 30 yards or roughly .017 miles in 2 seconds how fast was the ball going in mph? Answered by Penny Nom. 





Successive Differences 
20170406 

From Twaha: Please find the equation of the sequence 1 2 4 7 11 16 22 Answered by Penny Nom. 





Is a large integer divisible by 2^n? 
20170328 

From Sahand: You are given number x that is very large (that large that it can't be divided by hand)
can we find out that x is divisible by 2^n or not? Answered by Penny Nom. 





More on calculating the area (acreage) of a foursided lot 
20170306 

From Kerri:
Can you please show the formula used to calculate areas as provided on this page:
Calculating the area (acreage) of a foursided lot Answered by Penny Nom. 





The inside diameter of a silo 
20170228 

From JOHN: I need to find the inside diameter of a cement silo with an outside circumference
118 ft and a wall thickness of 7 inches. thank you John Kerr. Answered by Penny Nom. 





Five equations 
20170116 

From Muhammed: A x 4 = E
B χ 4 = E
C + 4 = E
D  4 = E
___________
& A + B + C + D = 100
what is the value of E Answered by Penny Nom. 





Cutting a wire into 18 cm lengths 
20161229 

From Shambhavi: A long wire of some length is cut into small pieces of 216 cm leaves a small piece of length of 89 cm of this part were cut into equal pieces each of 18 cm the length of the left over wire would be Answered by Penny Nom. 





Simultaneous equations with fractions 
20161221 

From Kimi: I am stuck on this,can someone please help me????
1/2x+1/3y=11
8x+2/5y=102
Can someone please explain how to solve questions like these??
Or else I will never learn...
Thank you Answered by Penny Nom. 





Divisibility of 3n^5+7n 
20161214 

From Parag:
Question from Parag, a student:
if n is a natural number,then 3n^5+7n is divisible by
a)2
b)3
c)5
d)7
i got the answer but still i need a valid alternate approach. Answered by Penny Nom. 





How far apart are the boats? 
20161213 

From Halley: Two boats leave port at the same time. Boat A travels east at a speed of 12 km/hr. Boat B travels southwest at a speed of 14 km/hr. After two hours, how far apart are the boats? North is 0 degrees. How do I figure this out.
Thanks Answered by Penny Nom. 





The sum of three integers is 30 
20161206 

From Vaishnavi: _+_+_:30. Blanks are to be filled by(1,3,5,7,9,11,13,15) and numbers can be repeated. Answered by Penny Nom. 





Three friends bought 13 books 
20161206 

From alexis: Marina bought 4 books Josι bought as many books as Ben bought together the 3 friends bought 13 books how many books did Ben buy Answered by Penny Nom. 





A pie chart 
20161205 

From vickie: Determine the central angle needed to form a pie chart for the following housing characteristic data: 63% owner occupied, 27% renter occupied, and 10% vacant Answered by Penny Nom. 





Simultaneous equations 
20161125 

From Rohan: x2/3 + y  1/4 = 13/12
2x/2 + 3 + y/3 = 11/6 Answered by Penny Nom. 





A square inside a circle inside a square 
20161113 

From Jeff: Greetings,
I came across a question from a textbook from years ago. I've been trying to solve it, but am not sure if my approach is correct.
There are 2 squares (1 inner, 1 outer) & 1 circle.
The inner square is the largest square that will fit inside the circle. It has an area of 1 unit.
The circle is the biggest that will fit in the outer square.
What is the area of the outer square? Answered by Penny Nom. 





The amount of material remaining on a roll 
20161111 

From Yoh:
Question from Yoh:
Hello,
I am trying to find impressions on a roll (either full roll or partial).
Let's say I have the following information.
 Outer Diameter of roll
 Inner Diameter of roll (cardboard core)
 thickness per layer
 Each cut off length (impression length)
Now let's say a roll has a 40in outer diameter, the cardboard core has a 3.75in diameter and a thickness of .002. Each impression has a cut off of 14inches.
With this the roll will have approximately 2,700 impressions. How would I find the remaining impressions if the outer diameter of the roll is only 6.5inches?
Thank you. Answered by Penny Nom. 





A pattern rule for a sequence 
20161028 

From Grace: Here's a Grade 7 question, we need to find the pattern rule:
1  1
2  3
3  6
4  10
......
It may involve exponents, but we can't seem to figure it out.
thank you.
Grace. Answered by Penny Nom. 





A word problem at the fair 
20161025 

From Rick: Have 48 tickets to spend, have to spend them all in exactly 10 events.
Rides cost 6 tickets games cost 4 tickets & treats cost 3 tickets Answered by Penny Nom. 





20/2 + 2 * 2^2 + 6 = 8 
20160915 

From Simone: 20/2 + 2 * 2^2 + 6 = 8
insert brackets to make this true Answered by Penny Nom. 





The radius of a coffee cup 
20160912 

From Brett: What is inside radius, in centimeters of a coffee cup if it holds 350g of coffee when filled to a depth of 9.5 cm? Assume coffee has the same density of water, 1.00g/cm3. A numeric value is expected and not an expression. Answered by Penny Nom. 





The dimensions of a rectangle 
20160831 

From Hazym: How do I find the length(which is 15m longer than the breadth) and the breadth of a rectangle just by its perimeter which is 70 m? Answered by Penny Nom. 





A suspension bridge 
20160818 

From sai: The main cable of a suspension bridge has the shape of a parabola. The cables are strung from the top of two towers, 61 metres apart, each 15.25 metres high above the roadway. The cable is 1.5 metres above the roadway at the point that is directly between the towers.
h(x)=a(x30.5)^2+1.5
where a is the constant and its value to be determined.
a) determine the value of the constant a by using that the fact that height of the suspension cable, h(x) is 15.25 metres at each tower. Hence, write the updated model equation. Answered by Penny Nom. 





Two lots 
20160808 

From Deniece: I have 2 lots that are joined together. One lot is 38' X 105' and the other is 45' X 105'. What is the total in acre size. Or, how close are these lots to make one full acre? I want to sell both lots and want to advertise using the total lot size. Thank you. Answered by Penny Nom. 





The dimensions of a rectangle 
20160725 

From Krunox: A rectangle is twice as long as it is wide. Its perimeter (the sum of the lengths of its sides) is 60 cm. Find its length and width. Answered by Penny Nom. 





The number of sides of a polygon 
20160723 

From Shriya: All the angles of a polygon are either 155° or 140°.
There are twice as many angles of 155 °or 140°.
Find the number of sides of the polygon Answered by Penny Nom. 





Two equations with fractions 
20160722 

From kanesh: p/2+q/3=3
p/4+2q/3=3 Answered by Penny Nom. 





The composition of a function with itself 
20160717 

From Mel: If f(1 + 3x) = 1 * x, solve f(f(x)) Answered by Penny Nom. 





A 1.4 acre square 
20160628 

From Jamie: Dear Faithfullness,
I was previously to be purchasing a square 1 acre plot, which I believe was to have 209feet, 4 sides perimeter.
How big would a 1.4 acre site be?
In sq feet length ie original 209ft + (the adeed 0.4) Answered by Penny Nom. 





Simultaneous equations 
20160625 

From sena: 2x/3+3y/2=1
4x5y=22
simultaneous equation Answered by Penny Nom. 





The lateral side length of a cone 
20160605 

From Diane: Question is find the lateral side length of a right cone with area of 372 sq. cm and base circle radius of 9 cm. Answered by Penny Nom. 





The area of a 4sided lot 
20160525 

From prasad: How to find area of a land whose sides are 41ft,33ft,32.3ft and 33.2 ft. Pl give me the formula and proof. Answered by Penny Nom. 





A trough with a triangular cross section 
20160521 

From Clarice: A trough having an equilateral triangle end sections has sides equal to 0.4 m and 7m long.what is the volume of the liquid in the container if the depth of the water is one half the depth of the trough? Answered by Penny Nom. 





The volume of a truncated rectangular pyramidal pond 
20160513 

From Paul: How do you calculate a partially filled truncated rectangular pyramid if you always know the bottom rectangle, the maximum height top rectangle perimeter, but have a varying height. Similar to filling up a pond you know the current height and dimensions at the max rectangle how do you calculate it half full i.e. 10x30 outside perimeter with a 2x8 base and a max height of 6ft how do you calculate it at 3ft without remeasuring the top perimeter.
Thanks,
Paul Answered by Harley Weston. 





A pair of equations with fractions 
20160511 

From tiya: hello, i want to know how to solve this question.
m/6+2n/3=6
m/10=2n/5=2 Answered by Penny Nom. 





At what time will Sara catch up with Jake? 
20160507 

From Laura: At 11:00 a.m., Jake started driving along a highway at constant speed of 50 miles per hour. A quarter of an hour later, Sara started driving along the same highway in the same direction as Jake at the constant speed of 65 miles per hour. At what time will Sara catch up with Jake? Answered by Penny Nom. 





A six digit code 
20160506 

From Ralph: How many combinations are possible if a "safe" has four buttons and you can use a six digit code? (these are just single press buttons..)For example, this could be one possible combination: Button 4 Button 1 Button 1 Button 3 Button 2 Button 4. Thanks! Answered by Penny Nom. 





Covering a site with 6 inches of rock 
20160426 

From Carla: if a pump house that measures 20'x16' sits in the middle of a site that is 50'x60' and you apply crushed rock to the site at depth of 6", how many yards will you need to haul? Answered by Penny Nom. 





External and interior angles of a regular polygon 
20160419 

From pearl: a polygon has n sides.The exterior angle is 8 times the interior angle
find the value of the interior angle
find the value of n Answered by Penny Nom. 





Conversion of an equation 
20160411 

From Marie: How to you convert the equation of a line from xintercept form
(y=(xx1)(xx2)) to general form (y=ax^2+bx+c) if it involves square
roots?
For example:
Convert this equation to general form: y=(x+the square root of 5)^2
Thanks for the help! Answered by Penny Nom. 





Filling a hole with 14 tons of rock 
20160408 

From Barry: If I had 14 tons of inch and one half sized aggregate rock, how large of a square or rectangular shaped hole would I need to hold that amount? Answered by Penny Nom. 





The remainder theorem 
20160327 

From Pratyasha: A quadratic polynomial when divide by x+2 leaves a remainder of 1 and when divided by x1 leaves a remainder of 4. What will be the remainder if it is divided by (x+2)(x1)? Answered by Penny Nom. 





Polynomial division 
20160325 

From Ashley: (4x4+6x^3x^2)/(3x2)
The instructions say to "perform the division". Answered by Penny Nom. 





A rotating schedule for a softball team 
20160325 

From Caroline: I couldn't find a similar question, hopefully there isn't one!
I have a softball team of 18 people (7 girls and 11 boys), but am limiting each game to 13 players (6 girls and 7 boys). The season is 10 games long. How do I create a rotating schedule which allows members to play evenly? I tried separating the boys and girls to create rotation for each but I got confused. Some are unable to attend all games but for the simplicity of a rotation schedule can you please help? Answered by Robert Dawson and Victoria West. 





The sides of a triangle 
20160315 

From Hitarth: Why we cannot construct a triangle ofngiven sides 5cm,5cm and 10cm? Answered by Penny Nom. 





Can you construct a regular 21gon? 
20160308 

From Peter: hi, i know that if i use a compass to draw a circle, i can use the same setting to mark 6 intervals along the circle circumference, how would i go about marking out 21 equally spaced points around the circumference?
if there an online calculator i can us, or some other interesting trick?
tia
peter Answered by Robert Dawson. 





A geometric progression 
20160303 

From Pauline: A woman measures the height of her child at birth and at monthly intervals afterwards.The child's height increases by 5% per month. Find the number of measurements she has made before the child's height is twice what it was at birth Answered by Penny Nom. 





Solve for x and y 
20160227 

From ntshidi: Y=1/2x+4and1/4x6 Answered by Penny Nom. 





How can I express Sin 4A in term of Sin A? 
20160222 

From Odukoya: How can I express Sin 4A in term of Sin A? Answered by Penny Nom. 





A bonus of 8% of sales 
20160222 

From Barghavi: A man earns $325 per week plus an additional 8% on any sales over $500.
If he makes $6,250 in sales, how much money in total does he earn that week?
thank you! Answered by Penny Nom. 





0/0 
20160214 

From Noni: Q. 0χ0=1 Why it is wrong when 4χ4=1; 3χ3=1; 2χ2=1: 1χ1=1 ? Answered by Penny Nom. 





Two equations in two unknowns 
20160213 

From Anumba: 4x + 2y = 4
7x  y = 11 Answered by Penny Nom. 





The midpoints of the sides of a quadrilateral 
20160205 

From Andrea: The segments, joining, in order the midpoints of consecutive sides of a quadrilateral form a parallelogram. Answered by Penny Nom. 





The height of a triangle 
20160203 

From Brooklyn: How do I figure out the height of a triangle when it only tells me the base of he triangle? And vice versa. Answered by Penny Nom. 





Division base 5 
20160201 

From Jenalee: I am having problems with a dividing bases question. I reviewed two that I could find in the database and tried the question as shown but I am still getting the wrong answer.
My question is 32\24043 to the base of 5 for both. Answered by Penny Nom. 





Simplify 
20160201 

From Sabira: Simplify step by step
5x/8 + 7y/18 = 6 Answered by Penny Nom. 





A system of linear equations 
20160124 

From kareem: my name is kareem
and i am a student i have a math puzzle and i tried to solved it but it always have same mistake
xy=9
x+z=12
zn=14
y+n=2 Answered by Penny Nom. 





The volume of a silo 
20160118 

From Clinton: Can you show me how to calculate the ground corn capacity in a steel silos of 10' x 10' high and 10' x 20' high and 10' x 24' high and 10' x 28' high Answered by Penny Nom. 





The perimeter of a one quarter acre square 
20160115 

From Kerry: If you have a perfect square that is one quarter of an acre what are the length of the sides and how do you arrive at the solution? thank you, Kerry. Answered by Penny Nom. 





A sequence 
20160105 

From Mia: the next three terms in each sequence. 0.4, 0.54, 0.68, 0.82, Answered by Penny Nom. 





Constructing simultaneous linear equations 
20151228 

From Deborah: Linda thinks of a twodigit number. The sum of the digits is 8. If she reverses the digits, the new number is 36 greater than her original number. What was Linda's original number?
Thank you! Answered by Penny Nom. 





Converting a fraction to a percent 
20151222 

From Sharon: How do you turn a fraction into a percentage? I'm beyond confused with this. Even though I think of myself as a good math student doing 8th grade math at a young age, this just makes me want to scream! I get the way you turn 1/4 into 25%, but when it comes to something like 7/9 = ? I just can't figure out the answer. Answered by Penny Nom. 





The angles of a triangle 
20151217 

From Faith: Does the measure of angle determine the length of its side? For example two angles are congruent then the sides are also congruent because from my understanding the angle determine the shape of triangle. Answered by Penny Nom. 





Sierpinski Pyramid 
20151214 

From victor: Is a tetrix (a Sirpienski Pyramid/Tetrahedron) its own hyperplane?...alternatively, is it a hyperplane? Answered by Robert Dawson. 





Linear equations in two variables 
20151213 

From priya: I have problem in solving these equations please help me today itself very urgent:
I)2x+y=y
II)pie*x+y=9 Answered by Penny Nom. 





Travelling in opposite directions 
20151206 

From Roselyn: Jenny and Mark commute to work, travelling in opposite directions. Jenny leaves the house at 8 AM, and averages 35 kph. Mark leaves at 8:15 AM, and averages 40 kph.At what time will they be 40 kilometers apart? Answered by Penny Nom. 





Dividing by a fraction 
20151121 

From Jennifer:
Question from Jennifer, a student:
I want to know how to get the right answer for this math problem, dividing a fraction in to a whole number , example 3/8 using the whole number 6? Thanks Answered by Penny Nom. 





A volume in cubic yards 
20151112 

From James: The first formula for figuring cubic yards of concrete need is length in feet, times width in feet, times depth in actual inches, divided by 320. Such as, 150x 50 feet x 4inches divided by 320 = cubic yards. How and why does this formula work? Answered by Penny Nom. 





Simplify 3(x7) 
20151021 

From geraldine: simplify: 3(x7) Answered by Penny Nom. 





A six team league to play a 20 game schedule 
20151019 

From Kelly: Hi there. Some of your posts are close, but my problem is evening out the home
and away games. We have 6 teams in our league and we are going to play a 20
game schedule, playing everyone 4 times. We will play Fridays and Saturdays,
each weekend. Of course the ideal would be to have each team have a home and
an away game each weekend, but I realize that is impossible, but I would like it as
close as possible. Any help would be much appreciated!! We also were considering
opening with a home and away  Friday then Saturday with the same teams. Then
carrying on with playing everyone else and then possibly finishing up with the same
home and home Answered by Victoria West. 





Six teams playing five games 
20151018 

From Aidan: I have six teams that will be playing five games.
I want each team to play each game once and each team to play each other team once.
Is this possible or should I add an extra round and let some teams play each other twice? Answered by Victoria West. 





The dimensions of a rectangle 
20150925 

From Erick: A rectangular strip of land has a perimeter of 124meters and an area of 385 square meters. Find its possible dimensions Answered by Penny Nom. 





A 6person team that has 9 players 
20150921 

From Sheri: I am organizing a 6person team that has 9 players. How do I schedule them fairly over a 9 week league? Answered by Victoria West. 





Seven switches with 3 stages each 
20150915 

From jeff: We are trying to solve a combination problem. If I have 7 things that can be in 3 states (say on/partially on/off), and all 7 have to a state. How many different combinations can there be? It doesn't seem like we should treat it as 21 independent things, but not sure how to break the problem apart. Answered by Penny Nom. 





Division and units 
20150908 

From Kenneth: Hello:
Would there be a reason to divide a number without units by another number with units?
Here is an example:
35 divided by $5.00 or 35/$5.00
The answer cannot have units ($) because $5 X 7 does not equal 35 but instead $35.00.
$35.00 divided by 5 or ($35.00/5) and $35 divided by $5.00 or ($35.00/$5.00) make more sense.
I thank you for your reply. Answered by Robert Dawson. 





Factor x^2 + y^2 
20150826 

From Jerome: Factor: x^2+y^2 Answered by Penny Nom. 





Four equations in 3 unknowns 
20150823 

From damien: solve:
S x U  T = 44
T  U x S = 36
U + T  S = 7
U x U / S = 4 Answered by Penny Nom. 





The length of a shadow 
20150801 

From maaz: Hello
I am having trouble with this question:
Lizzie, who is 6 feet tall, stands in her driveway at night, exactly
24 feet from the base of a spotlight, and casts a shadow that is 12
feet long if her friend Hannah who is 5 feet tall decides to stand
next to lizzie how long will her shadow be? Answered by Penny Nom. 





1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 x 0 + 1 = ? 
20150618 

From Sharon: 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 x 0 + 1 = ?
I got 1 as my answer despite BODMAS making it 12 because logic tells
me I ought to place brackets around the first set of repeated addition. Could you
please clarify this for me? Thank you 😊 Answered by Harley Weston. 





An octagonal frame around a pool 
20150517 

From James: I have a 20' pool and need to put a frame around it using 2by 4 what r the lengths and angle cuts Answered by Penny Nom. 





An angle of depression problem 
20150514 

From haxir: find the height of the balloon directly above a town if the measure of angle of depression of another town 5km from the first town is 20°!6` Answered by Penny Nom. 





Repeated decimals 
20150509 

From Vir: Years ago I (re?)discovered 'cyclic division'. For example: if you arrange the number along a circle and put the number 142857 at the centre
all the numbers taken cyclically, starting with 1, are fully divisible by 37. Whatever the starting point of this number, it remains fully divisible by 37.
what is more, the number can be formed by taking the digits clockwise as well as anticlockwise..This I call "full cyclic divisibility". In many cases, only clockwise cyclic divisibility is possible. But I have not come across a case where ONLY anticlockwise divisibility occurs. Thus clockwise cyclic divisibility seems to be favoured. Could this be construed as a sign of chirality in mathematics?.. Answered by Chris Fisher. 





The number of possible musical notes using an nkey instrument 
20150504 

From Farihin: Lets say that i have keys, and each key is for notes of a musical instrument,
So i wanted to find out the number of notes i can get for a certain number keys,
of course in the form of an equation. Notes can use as many keys, it can use 1, or 2, or 3, or even 100.
Notes in real life is not as such, but ignore reality.
I tried doing this but i can't seem to find a formula for it.
For example, i have 4 keys, say A, B, C, and D.
so, for notes that uses one key are 4, which is A, B, C, and D themselves.
for notes that uses two keys are 6,
AB, AC, AD, BC, BD and CD.
for notes that uses three keys are 4,
ABC, ABD, ACD and BCD.
lastly for notes that uses all four keys is 1, ABCD.
So, the total will be 4+6+4+1=15#
The nth term for the first equation is n, the second is [(n^2)n]/2
the third and the fourth, i don't know but the final answer should be like,
n + [(n^2)n]/2 + [3rd] + [4th]
Sorry for the long question though... Answered by Penny Nom. 





13 games, 3 possible outcomes 
20150501 

From Kennedy: Hello, hope it finds you well.
Am not that good with numbers, can you please help me get all the possible outcomes of 13 games, with a home win, draw or an away win as three possible results for each of the 13 games.
Thanks in advance Answered by Penny Nom. 





The method of elimination 
20150501 

From oreanna:
Question from oreanna, a student:
How do u solve 2x+9y=3
7x4y=25 in elimination Answered by Penny Nom. 





Expand and Simplify (3x+5)(5x9) 
20150423 

From chloe: Expand and Simplify (3x+5)(5x9) Answered by Penny Nom. 





How many boats total are in the marina? 
20150415 

From Carla: In a marina, 3/4 of the boats are white, of the remainder 4/7 are blue, the rest are red. There are 9 red boats. How many boats total are in the marina? My answer is 84 because if 1/4 of the boats are divided into sevenths, that makes the whole marina a 28 part item. 3/28 are red so 84 is the total number of boats. My child thinks I am wrong. Answered by Penny Nom. 





Two airplanes 
20150414 

From john: two planes leave an airport at the same time, one going northwest (N35*W)at 400 mph and the other going east at 332 mph. How far apart are the planes after 4 hours to the nearest mile? Answered by Penny Nom. 





Some nondecreasing sequences 
20150413 

From Sky: Hi I'm a Student and i'll try my best to state the problem perfectly.
The number of nondecreasing sequences of size at least 1 and at most N,
such that each element of the sequence lies between L and R, both inclusive.
Eg: N=1 L=4 R=5
ans= 2. [{4},{5}]
N=3 L=4 R=6
ans= 19. [{4},{5},{6},{4,4},{4,5},{4,6},{5,5},{5,6},{6,6}
{4,4,4},{4,4,5},{4,4,6},{4,5,5},{4,5,6},{4,6,6},{5,5,5},{5,5,6},{5,6,6}
,{6,6,6}] Answered by Claude Tardif. 





A word problem with fractions 
20150409 

From Lorraine: If the numerator of a certain fraction is doubled and the denominator is increased by 1, the fraction becomes 1/2.
If the numerator of the original faction is squared and the denominator is decreased by 2, the fraction becomes equal to 1.
Let x be the numerator and let y be the denominator of the original fraction.
Write down two simultaneous equation in x and y.
Solve these equations to find two possible values for the given fraction. Answered by Penny Nom. 





The weight of a steel block 
20150404 

From Mark: the weight of a steel cube 37 inches X 28 inches X 7 inches Answered by Penny Nom. 





The side length of a gazebo 
20150314 

From Dennie: From middle of side to middle of opposite is 14'6". What is the length of the side? Answered by Penny Nom. 





Commission 
20150313 

From Rose: A shopkeeper receives 12.5% (12 1/2 %) commission on the sale of books from
the publisher. In a certain month,he receives a commission of rs.250 from the
publisher. How much was his sale for that particular month?? Answered by Penny Nom. 





Angles of elevation and depression 
20150308 

From Timmy: Joel is walking down a street and sees a 115 ft tall building in front of him. He stops 190 feet from the base of the building at the tip of the building's shadow. Round answers to three decimal places.
A. If there was a piece of rope from the top of the building to Joel, how long would it be?
B. What is the angle of elevation from Joel to the top of the building?
C. Margaret says that she could find the angle of depression from the top of the building to Joel by subtracting the angle of elevation from 90°. Is she correct? Explain. Answered by Penny Nom. 





The definition of percent ( % ) 
20150307 

From Kenneth: Hello:
I saw this definition online from the Free Dictionary (The Free Dictionary.com) regarding the definition of percent (%):
"Noun 1. a percent sign  a sign (`%') used to indicate that the number preceding it should be understood as a proportion multiplied by 100."
What is this "proportion" multiplied by 100?
When I think of a proportion, I think of a/b = c/d. How can a number preceding the percent sign be understood as a proportion X 100?
I thank you for your reply! Answered by Chris Fisher and Claude Tardif. 





A man is standing on top of a building 
20150306 

From kiki: a man of height 1.5m standing on top of a building of height 48.5m views another building across the square. he observe that the angle of depression of the bottom of the building is 40 degrees and the angle of depression of the top of the building is 5 degrees. Both buildings stand on the same level
a) calculate the distance of the man from the base of the building across the square measured along the line of sight Answered by Penny Nom. 





Two consecutive positive integers 
20150301 

From meha: Find two consecutive positive integers , sum of whose squares is 365. Answered by Penny Nom. 





Two equations with fractions 
20150226 

From Pulane: Hi math centre I've been trying to solve these equations for days now please help
(6/x)(1/y)=4
(9/x)+1=(2/y)
Please help me solve them simultaneously
Thank you Answered by Penny Nom. 





3 over "x" plus 5 
20150223 

From Kenny: 3 over "x" plus 5. I don't know this is either a polynomial and if so how would you define it. Answered by Harley Weston. 





Two equations 
20150216 

From nigel: 2x+1/2y=1
6x3/2y=21 Answered by Penny Nom. 





A stone is dropped in a lake 
20150214 

From Wendy:
Hi, I have problems solving this problem. We didn't exactly go over these kind of problems and the book doesn't have an example either. Thank you for your help!
A stone is dropped in a lake, creating a circular ripple that travels outward at a speed of 80 cm/s.
(a) Find a function g that models the radius as a function of time t.
g(t) =
(b) Find a function f that models the area of the circle as a function of the radius r.
f(r) =
(c) Find f compose g.
f compose g = Answered by Penny Nom. 





The volume of Lake Utah 
20150129 

From Hannan: Lake Utah has a surface area of 3,846 square miles and an average depth of 10.5 feet. In cubic miles, how much water does it hold?
How would you approach this question? Where would you start? Answered by Robert Dawson and Penny Nom. 





128/(16)/(2) 
20150128 

From jackie: 128/(16)/(2) I was wondering if you can show me how to work this question out Answered by Harley Weston. 





Is a square a trapezoid? 
20150126 

From Katie: Can a trapezoid sometimes be a square? Answered by Penny Nom. 





sin x = cos x 
20150123 

From Mubashir: there are two curves y=sinx and y=cosx intersecting at point where x is less than 90 and greater than 0.to find the point I made a equation sinx=cosx
but donot know what to do further .please help me by solving this equation sinx=cosx
also tell me that have you solved this equation by reference to the graph or by other means please do elaborate your solution in your answer. Answered by Penny Nom. 





The height of a building 
20150120 

From Emily: A man 2m high observes the angle of elevation to the top of the building to be 70 degrees. And the angle of depression to the bottom of the building to be 19 degrees. How tall is the building? Answered by Robert Dawson. 





Pumping water from a borehole 
20150118 

From patience: An empty tank for storing water from a borehole has a volume of 480 cubic metres. If it is filled by a pump that pumps water at a rate of 16 litres per second, how many hours will it take the pump to fill this tank please show all calculations Answered by Penny Nom. 





Mutually prime composite numbers 
20150109 

From nivedita: Two composite number that is mutually prime? Answered by Penny Nom. 





Missing digits in a phone number 
20150107 

From Janelle: I had a friend try and play a game on me, regarding phone numbers, so I only know the area code , and the last four digits of the phone number. Which means, there are 3 digits that I need to figure out all the possibilities to. Answered by Penny Nom. 





A silo is composed of a hemisphere and a cylinder 
20150103 

From Ami: A silo is composed of a hemisphere and a cylinder. The total height for the silo is 20m and the diameter of the silo is 8m. What is the volume of the silo to the nearest cubic meter? Answered by Penny Nom. 





1 + 2 + 3 + ... + (2n  1) 
20150101 

From Brian: Hi Maths Central
My wife presented me with a query which may have a simple answer, but one that I cant deduce or explain.
Take the string of numbers, n=1,2,3,4,5
It seems that n(2n1) = Sum((1
..(2n1))
e.g. for n=5, both 5 x 9 and Sum(1
.9) equal 45, and so on for other values of n.
Could you please provide an explanation? Does it have an underlying reason and a name?
Look forward to your response.
Brian Answered by Penny Nom. 





Rates, percentages and units 
20141230 

From Kenneth: Hello:
If percentages have no units, why are some percentages called rates, as in interest rate, or
perhaps a tax rate of 7% as an example? A rate has units of different quantities.
I thank you for your reply. Answered by Robert Dawson. 





Remainder 
20141208 

From Muqadasah: A number, when divided by136, leaves remainder 36. If the same number is divided by 17, what will be the remainder? Answered by Penny Nom. 





How do you change a decimal to a ratio? 
20141129 

From Esmeralda: How do you change a decimal to a ratio? Express the decimal 0.2 as a ratio. Answered by Penny Nom. 





An arithmetic progression 
20141119 

From Gbenga: In an A.P the difference between 8th and 4th term is 20. The 8th term is 1\2 times the 4th term . Find arithmetic progression.. Answered by Penny Nom. 





How many square feet in 10 gallons of liquid at 1/4 in thick? 
20141114 

From Rich: How many square feet in 10 gallons of liquid at 1/4 in thick Answered by Penny Nom. 





1/6k=11 
20141113 

From Marty: Using the balance method, what is the answer to 1/6k=11, trying to find what k equals. Thanks Answered by Penny Nom. 





The density of sea sand 
20141102 

From Lenny: Hi There,
I need to find out the the density of sea sand to convert one metric ton to cubic
meter as I am submitting for a tender which is in cubic meter but the requirement
is in metric ton. I searched through the web site but no density of sea sand is given
though there is specific Gravity of dry sand is available. I was given a density of
1.6 to work with. If that is true am I right to say that 1 cubic meter of sea sand is
equivalent to 1.6 metric ton? Please help as I am getting confused with what I am
able to find out on the web.
Thanks much in advance
Rgds
Lenny Answered by Penny Nom. 





A linear system 
20141014 

From pheter: 4/x  1/y = 3 .... equation (1)
6/x  2/y = 5 .... equation (2) Answered by Penny Nom. 





A fact family containing 4, 4 and 16 
20141014 

From Leslie: I am helping my son and the question is 4,4,16 in fact family what does that mean Answered by Penny Nom. 





Building an 8 sided box 
20141014 

From Michael: I want to build an 8 sided box. The North, East, South, and West sides I want them to be 4 feet in length.
The NE, SE, SW, and NW sides I want to be 2 feet in length. What angles do I need to cut my angles.
Thanks Michael Answered by Penny Nom. 





Sieve of Eratosthenes 
20141003 

From Hope: using Sieve of Eratosthenes to determine for in instance prime numbers between 1 to 200, to what nth number should i stop?, 4th, which is 11 or what? Answered by Robert Dawson. 





Trig functions and the unit circle 
20141002 

From Jake: I was wondering what conclusions can be drawn about the trigonometric functions and how they work about the circle. Can you also please give me an explanation for it? Thank you. Answered by Penny Nom. 





Division in base 3 
20140930 

From Nnubia: 1021 in base 3 divided by 2 in base 3 Answered by Penny Nom. 





A rectangle and a triangle 
20140927 

From rajesh: The perimeter of a rectangle is equal to the perimeter of a rightangled triangle of height 12 cm if the base of the triangle is equal to the breadth of the rectangle, what is the length of the rectangle? Answered by Penny Nom. 





Two equations in x and y 
20140925 

From seyilogo: solve y=2x  3 and (4x  2y) / x + y = 1 simultaneously Answered by Harley Weston. 





Two equations in two variables 
20140918 

From Susan: (28x + 36y)  [20000  .75(28x + 36y) + 60000] = 5000
x + y = 10000
solving two equations involving variables Answered by Penny Nom. 





A six team track schedule 
20140915 

From Paul: I need to make a six (6) team track schedule. It needs to be five (5) triangular (3 team) meets with each team playing each team twice Answered by Victoria West. 





Cutting a round cake so that it doesn't dry out 
20140826 

From James: I'm wondering if there's a simple way to calculate the area between two parallel chords of a circle equidistant from its diameter, or if I have the area, to find the distance between the two chords.
Here's my "problem". You may have heard of the way of cutting a round cake so that it doesn't dry out  make two parallel cuts (chords) the length of the cake, take the middle piece, then push the two pieces together.
So I know the area of a 12" cake, and I want say, exactly an eighth of the cake. How wide do I cut the centre piece?
Now to get even more difficult, the next day I want another eighth from the centre. How wide do I cut the next pieces, and so on...?
Thanks,
James Answered by Harley Weston. 





Revisiting 8 golfers in two foursomes 
20140819 

From steve:
I noticed you had an answer on how can you put 8 golfers in even foursomes over 7 games so that everyone plays with everyone equally. However the formula showed the following sequence that was used but did not go past the second day. Can you change the 0s and 1s into the numbers 1 to 8 instead. Here is what you have written:
Day 0 : (0, 0, 0, 0, 1, 1, 1, 1)
Day 1 : (0, 0, 1, 1, 0, 0, 1, 1)
Day 2 : (0, 1, 0, 1, 0, 1, 0, 1)
Day 3 : (0, 1, 1, 0, 1, 0, 0, 1)
Day 4 : (0, 0, 1, 1, 1, 1, 0, 0)
Day 5 : (0, 1, 0, 1, 1, 0, 1, 0)
Day 6 : (0, 1, 1, 0, 0, 1, 1, 0)
Thank you so much for your anticipated help.
Steve Answered by Harley Weston. 





A barge of triangular cross section 
20140818 

From tushar: a barge of triangular cross section is 20m long 12 m wide and 6m deep.its floats in SW at a draft if 4m find its displacement Answered by Penny Nom. 





How do you convert square mm to square cm? 
20140813 

From David: How do you convert square mm to square cm? Answered by Tyler Wood. 





4821x14y is an 8digit number divisible by 72 
20140806 

From RAYA: if 4821x14y is an 8digit number divisible by 72. How many values can x and y take? Answered by Penny Nom. 





The dimensions of a rectangle 
20140803 

From Jamaica: if the perimeter of a rectangle is 30m and its area is 56 m2.find its length and width? Answered by Penny Nom. 





The sum of the first 50 terms of an arithmetic progression 
20140726 

From Joshua: Hello ...my is Joshua...I'm a grade 11 student...I got a question
Calculate the sum of the first 50 terms of an arithmetic progression: 112:98:84 Answered by Penny Nom. 





An octagon around a tree 
20140716 

From floyd: I want to build an octagon 4 feet from base of tree from 4x4's. What length do I cut my pieces Answered by Penny Nom. 





Solve sin3x = cos2x 
20140714 

From Emanuel: If sin3x=cos2x, find the value of x when x<0<90' Answered by Penny Nom. 





A 5 sided lot 
20140710 

From mia: have the feet numbers of three sides, but the forth side is in a "V" so it has two figures.
Question: can i add the two figures of the "v" together to get one figure, so then I would have the figures for all four sides. Answered by Harley Weston. 





67 cubic yards in cubic metres 
20140709 

From gavin: Convert 67 cu yards into cu metres Answered by Penny Nom. 





The method of elimination 
20140705 

From leo: please explain how can i solve this problem
3x6y=38
6x9y=44
using elimination and simultaneous method thank you :) Answered by Penny Nom. 





A six digit number 
20140630 

From anupam: hi,
my daughter asking a solution for the below question, kindly help.
Write the smallest 6 digit number wit digits ( 2,4,3,0,5,7).
plz this is an urgent requirement.
regards,
anupam Answered by Penny Nom. 





Simultaneous equations 
20140620 

From rana: solve the simultaneous equations
a)3x=7y
12y=5x1 Answered by Penny Nom. 





Two regression lines 
20140614 

From catherine: Given a set of data values ,we can get two regression lines .Explain. Answered by Robert Dawson and Penny Nom. 





A small solid silver pyramid 
20140613 

From Jenesis: For Awards Night at Baddeck High School, the math club is designing small solid silver pyramids.The base of the pyramids will be a 2 in by 2 in square. The pyramids should not weigh more than 2.5 pounds. One cubic foot of silver weighs 655 pounds. What is the maximum height of the pyramids? Answered by Penny Nom. 





The weight of salt in a basket 
20140517 

From Sumit: I want to determine how many kg of salt or XYZ thing can be filled in a basket
Length = 4.5"
Breadth = 5"
Height = 6"
Even its formulae
is kg quantity can be different for semi solid thing Answered by Penny Nom. 





The length of a shadow 
20140509 

From vijay: A girl of height 80 cm is running away from the base of a lamppost at a speed of 2 m/s. If the lamp is 4 m above the ground, find the length of her shadow after 5 seconds. Answered by Penny Nom. 





A cone of vision 
20140429 

From David: It is known that a fish in water looking up has a 97 degree "cone" of vision that sees "through" the surface of the water. If a fish lies 4 inches below the surface, the cone forms a window (circle) smaller than if a fish lies 8 inches below the surface. What is the ratio of inches of depth to the radius of the circle on the surface that is its visual window? Answered by Penny Nom. 





A triangular chicken pen 
20140427 

From Cierra: Margaret has two lengths of fence, 20 meters and 24 meters, for two sides of a triangular chicken pen. The third side will be on the north side of the barn. One fence length makes a 75° angle with the barn. How many different pens can she build if one fence is attached at the corner of the barn? What are all the possible lengths for the barn side of the pen?
Not sure what they are asking here... please show step by step what to do! Thank you so much! Answered by Penny Nom. 





The derivative of sin(x) 
20140426 

From Lucky: f(x)=Sin(x), by first principle its f'(x)...show me how to solve such problem. Answered by Penny Nom. 





Simultaneous equations with fractions 
20140419 

From Maryam: I looked at your example of simultaneous equations with fractions and applied it to my question from an educate exam papers but I couldn't get it to work. The question is:
x/8  y = 5/2
3x + y/3 = 13 Answered by Penny Nom. 





A slab of wet clay 
20140412 

From Karen: How many square feet ( at 1/4 inch thickness) are in 100 lbs. of wet clay? Answered by Penny Nom. 





Two cones 
20140409 

From c.j: what is the length of the radius of the LARGER cone(the LARGER cone has a slant height of 15) when the SMALLER cone has a radius of 8 and a slant height of 12ft ,please help. Answered by Penny Nom. 





The sides of a triangle 
20140406 

From Michael: I am supposed to sove for the length of side "b" of an irregular triangle. I am given the following:
Side a: 65'
Side b: Find this length
Side c: 50'
Angle A: unknown
Angle B: unknown
Angle C: 52 degrees
I am supposed to use the law of cosines to solve for side "b" and my teacher
says there is no mistake in the "givens" for the problem. I do not see how
this can be done using the law of cosines and i have not figured out how to sove for
angle B to use the law of cosines. Answered by Penny Nom. 





A 4 digit number 
20140404 

From LIM: "A" is a 4 digit number formed by all the numbers from 1 to 4. When "A" is divided by 9, the remainder is the biggest possible value. What is the biggest value of A? Answered by Chris Fisher. 





Shadows of a father and son 
20140402 

From esada: the father and son cast a shadow of 11 feet and 8 feet,respectively if the son is 4'8'' in height,how tall is the father? Answered by Penny Nom. 





Reducing the size of a poster by a scale factor of 1/3 
20140401 

From deeshon: eric is making a smaller copy of a poster that measures 20.4 cm wide by 34.2 cm long.he reduces the original by a scale factor of 1/3.what are the dimensions of the copy Answered by Penny Nom. 





An arithmetic progression 
20140331 

From Japheth: The 3rd term of an A.P is 10 more than the first term while the fifth term is 15 more than the second term. Find the first term? Answered by Penny Nom. 





A formula for determining concrete volume in cu. yd. 
20140319 

From Steven: I know a couple of formulas for determining concrete volume in cu.yd. the one I use most frequently is length in feet x width in feet x thickness in inch. Divided by 324. It works every time. Where does the number 324 come from. Answered by Penny Nom. 





The area of a 5 sided lot 
20140315 

From Michael: Question from michael:
This lot is in feet. 59x154x109x188x137 per the plot plan Answered by Harley Weston. 





A parabolic suspension bridge 
20140311 

From jeffrey: the towers of a parabolic suspension bridges 200 meter long are 40 meter high and the lowest point of the cable is 10 meter above the roadway.Find the vertical distance from the roadway to the cable at 50 meter from the center. Answered by Penny Nom. 





Simple interest 
20140308 

From lynn: I need to find what the interest will be for: 5000.00 @ 16.5%
annual rate, and the same for 10.8 % for 5000.00 annual rate all one question
thank you for your aid Answered by Penny Nom. 





The angle of depression 
20140308 

From Ranger_minor: A woman of height 1.4 metres standing
on the top of a building 34.6 metres high
views a tree some distance away.
she observes that the angle of depression of the bottom of the tree
is 35 degrees and the angle of depression of the top of the tree
is 29 degrees.
assume that the building and the tree are on level ground :
1). calculate the distance of the woman
from the top of the tree measured along her line of sight. Answered by Penny Nom. 





Simultaneous fractional equations 
20140215 

From benjamin: hi math central. benjamin here. during class, i had problem with this topic. normally i wont have problems with math but this topic i just too hard for me. please help i am having exam and test next week on this topic
here is the question:
using substitution method, solve the simultaneous equation.
(x+1)/(y+2)=0.5
(x2)/(y1)=1/3 Answered by Penny Nom. 





Converting cost per cubic yard to cost per ton 
20140205 

From Mayra: If 18 cubic yards= 25 tons and it's $28.00 per yard how much is it a ton. I need help please a refresher on my algebra. Thank you Answered by Penny Nom. 





Two nonlinear equations 
20140126 

From Naryn: (1χx) + (1χy) = (7χ12)
xy = 12 Answered by Penny Nom. 





When would one flip the inequality sign? 
20140109 

From Natasha: Would one flip the inequality symbol in this equation: (explain why)
(9a)/(9) > 81
And please explain in what circumstances one would flip the inequality sign
THANKS! Answered by Penny Nom. 





An arithmetic sequence 
20140106 

From paris: find the twentyfifth term of an arithmetic sequence whose first term is 12 and whose common difference is 6 Answered by Penny Nom. 





25% profit 
20140102 

From Finn: Hello,
The question is all about buyandsell business.
Problem:
Pencil  $6 for whole sale price
$8 if I sell the item
How do I get the 25% profit? (you can change the whole sale price and the retail price[if i sell the item])
if I buy the pencil at 24 pieces and sell it at 24 pieces. Answered by Penny Nom. 





0.35 as a fraction 
20131128 

From Laura: How do you write 0.35 as a fraction or mixed number?
Laura Answered by Penny Nom. 





Substitution type simultaneous equations 
20131103 

From Kayla: I am having problems with substitution type simultaneous equations, when the variable you are substituting is a algebraic one:
y=x^23x+4 and 3x2y=1
I have rearranged 3x2y=1 to get x=(1+2y)/3 but when I substitute this x value into the other equation, I get the wrong answers!
Would appreciate any help! Thank you. Answered by Penny Nom. 





Proportional rates 
20131010 

From Varsha: A province's Ministry of Social services has found that both the number of people needing social assistance and the province's total expenditures on social assistance are proportional to the rate of unemployment. Last August when the provincial unemployment rate was 8.4 %, the province provided assistance to 89,300 individuals at a total cost of 4107.4 million. The forecast unemployment rate for next August is 7.9%. How many people can the province expect to need social assistance next August? What amount should the province budget for social assistance in August? Answered by Penny Nom. 





How many cubic centimetres are there is a cubic meter? 
20131010 

From Larry: Change 1meter(to 3rd power) to centimetre(to 3rd power).
This is a metric conversion problem Answered by Penny Nom. 





An Arithmetic Progression 
20131008 

From collins: In an A.P. the difference between the 8th and 4th term is 20 and the 8th is one and half times the 4th term... what is the common difference and the first term Answered by Penny Nom. 





A triangle problem 
20131002 

From raneem: ABC is a triangle in which : BC=20cm. M(<B) =29 and m(<C)=73 . D is the midpoint of BC
Find the length Of AB and AD approximated to 2 decimal places Answered by Penny Nom. 





A schedule for 2, 7 team divisions 
20130924 

From Sampson: I'm looking to set up a weekly schedule within a 22 week segment of 2 7 team divisions where every team plays every other team in their divison 3 times and have 4 cross over games with 4 of the other 7 teams in the other division. I've yet to figure this out.
Thanks for your time. Answered by Victoria West. 





Miles per minute to miles per hour 
20130908 

From Adam: Convert 250 miles per min to miles per hour Answered by Penny Nom. 





How we convert cm to mm? 
20130908 

From Gιnesis: How we convert cm to mm? Answered by Penny Nom. 





The sum of all whole numbers from 1 to X 
20130906 

From Tim: How do I develop a rule for the sum of all whole numbers from 1 to X when I have no idea how to do this Answered by Penny Nom. 





A sequence or a series? 
20130905 

From Rahul: Whether the following sequence is increasing or decreasing? I even do not kow whether to call it a sequence or not. an = (1/(1+n))+(1/(2+n))+....+(1/(n+n)).
I am confused. It looks like a series to me. Please help.
Regards,
Rahul Answered by Robert Dawson. 





Tesseract 
20130822 

From Dan: I am not a mathematician. This seems to me an intuitively simple enough problem that I very much need an answer to from someone who's mathematics are better than mine. Please help.
The question is: for a tesseract of side length = 1
what is the distance of the center of each cube from the center of the tesseract ?
I think I have calculated the distance of each vertex from the center, and of the center of each edge from the center, but the question above baffles me.
(anyone not having a clue what I am talking about can brush up here http://en.wikipedia.org/wiki/Tesseract )
Thanks in advance  Dan V Answered by Robert Dawson. 





Similar rectangles 
20130817 

From Mattie: The dimensions of a rectangularshaped picture frame are 14 inches long and four inches wide. Which dimensions below represent another frame that i geometrically similar>
a. l=49 in. and w=14in.
b. l=7in and w=3in
c. l=21in and w=8in
d. l=24in and w=14in
thanks Answered by Penny Nom. 





Using trig to find the height of a hill 
20130814 

From Anna: From the top of a hill, the angles of depression of two successive milestones on a level road, which leads straight away from the hill, are 5degrees and 15degrees respectively. Fine the height of the hill.
Suggestion: BE is drawn perpendicular to AD. Find BE, then BD, finally CD.
Thanks :) Answered by Penny Nom. 





A triangle construction 
20130727 

From Nazrul: Two angles and the difference of the lengths of their opposite sides of a
triangle are given. How can I draw the triangle.
Please help me. Answered by Chris Fisher. 





What is the smallest number? (i.e. the closest number to zero) 
20130722 

From Charlie: What is the smallest number? (i.e. the closest number to zero) Answered by Harley Weston. 





Simultaneous equations 
20130710 

From Warren: solve this simultaneous equation: xy=4
2x+3y=14 Answered by Penny Nom. 





An arithmetic progression 
20130706 

From ashok: the 4th and 10th term a.p respectively 7 and 19 find its 15th term..... Answered by Penny Nom. 





A 3 acre plot 
20130617 

From Chad: I have 3 acres 100ft at the top and bottom what is the length of each side to make up the 3 acres Answered by Penny Nom. 





{(1+x)^1/31/3X(1+x)^2/3}/(1+x)^2/3 
20130617 

From STEPHEN: {(1+x)^1/31/3X(1+x)^2/3}/(1+x)^2/3 Answered by Penny Nom. 





An isosceles tiangle 
20130616 

From Izzy: what's the height of an isosceles triangle which has a base of 50 m, and both of the other sides are 25 m? Answered by Penny Nom. 





Simson line 
20130523 

From Nazrul: From any point p lying on the circumcircle of the triangle perpendiculars
PD , PE are drawn on BC,CA respectively. The line segment ED intersects at
the point 0 ; prove that PO ⊥ AB ( PO is perpendicular to AB ). Answered by Chris Fisher. 





A 2digit number 
20130513 

From A teacher: Find a 2digit number where the sum of the 1st digit (on the Left)
and the square of the 2nd digit equal the same number. Answered by Lorraine Dame, Harley Weston. 





siin (A) and sin (A/2) 
20130509 

From shanaia: given that sin A=4/5 and A is obtuse.find sin (A/2) Answered by Penny Nom. 





A silver figurine 
20130503 

From Renee: I have a silver figurine, the density of silver is 10.5g/cm3. if the figurine weighed 149 g. to determine the volume, he dropped it into a cylindrical glas of water. the diameter of the glass is 6 cm and the figurine was pure silver, by how much should the water level in the glass rise? Answered by Penny Nom. 





How can we draw the equation "x+y=1" in 3d? 
20130503 

From shimaa: how can we draw the equation "x+y=1" in 3d Answered by Robert Dawson. 





How do i reverse this formula? 
20130420 

From MK: I have 22,000,000 worth of gold and wants to want to resell the gold back with a profit.
Each transaction of gold will have a transaction fee of 15%, so if i resell the gold back at 22,000,000, I will only get back 18,700,000 after 15% transaction cut.
The current formula is X15%X = Y where X = 22,000,000 and Y = 18,700,000
Will u be able to come up with a new formula if we don't know the value of X but we know the value of Y
Something like this X15%X = 22,000,000.
How do i reverse this formula to find the value of X
Thanks Answered by Penny Nom. 





4 linear equations with 3 unknowns 
20130412 

From Marian: how to solve for 3 unknowns in 4 simultaneous equations Answered by Penny Nom. 





The distance between 2 lines in 4D 
20130401 

From samane: how can i measure the distance between 2 lines in 4D?? Answered by Chris Fisher. 





We can't write sinx and cosx as a finite polynomial. 
20130331 

From rimoshika: prove that we can't write sinx and cosx as a finite polynomial. Answered by Walter Whiteley. 





Simultaneous equations with fractions 
20130331 

From Terence: 5/x6/y=1
17/x+30/y=16
I been spending whole day to solve this question. Would be very grateful if you can help I try
The denominator value is a equations term which make is simultaneous equations so hard. Answered by Penny Nom. 





The dimensions of a rectangle 
20130319 

From stephanie: the length of a rectangle is 5m more than twice its width, and the area of the rectangle is 88m^2 find the demensions of the rectangle Answered by Penny Nom. 





Sixdigit passwords 
20130319 

From Judy: Hello:
Can you please explain why the answer to the following question is 10^6?
What is the number of possible sixdigit passwords when using the digits 0 through 9, with repetition allowed.
Thank you. Answered by Penny Nom. 





An algebraic exercise 
20130318 

From autumn: given: f(x)=x/(x^2+2) determine: [f(xh)f(x)]/h Answered by Penny Nom. 





A messy arithmetic expression 
20130224 

From niiaryee: (((((5^2*4^3)1/5+9^3/3)+(25+(4*5)/15)^210)/10/2)3))))) Answered by Penny Nom. 





Fractions over fractions 
20130222 

From Kenssa: Question from Kenssa, a parent:
Simplify: 3(7/x)(6/x^2) / (3/x^2)+(5/x)2 Answered by Harley Weston. 





The continuity of f(x,y)=ln(x^2+y^2) 
20130217 

From anu: the question says we have to find the points in the plane where the function is continuous:
f(x,y)=ln(x^2+y^2) . here we aren't given a particular point (x,y) where we have to check a function's
continuity.
what is to be done if we have to check continuity over the whole domain of the function?
please help . Answered by Harley Weston. 





A word problem involving toys 
20130214 

From sandy: Each boy gets 5 toys.Each girl gets 3 toys.There are 150 pupils.
The boys had 74 more toys than girls.
How many boys?
How many girls? Answered by Penny Nom. 





Simultaneous equations 
20130210 

From Michael: 2P + 1/3V =8
3P  2/V=5 Answered by Penny Nom. 





An arithmetic progression 
20130206 

From loberto: the 3rd term of an a.p is 10more than the 1st term,while the 5th term is 15more than the 2nd term,find the sum of the 8th and 15th terms of the a.p if the 7th term is 7times the 1st term Answered by Penny Nom. 





A relation on a collection of sets 
20130204 

From raji: suppose R be a non empty relation on a collection of sets defined by ARB if and only if A intersection B is nullset.then.....the correct answer is R is symmetric and not transitive...my doubt is how it is symmetric Answered by Penny Nom. 





The fourth side of an irregular polygon 
20130201 

From Emran: I have a irregular polygon. I know 3 of the 4 sides, and 2 of the angles. AB is 285, BC is 149, and CD is 310. Angle B is 135 degrees. and Angle C is 45 degrees. Is there a formula to solve for the final side? Thanks. Answered by Penny Nom. 





The weight of a pipe full of water 
20130116 

From joe: how do you figure out the weight of a pipe full of water Answered by Harley Weston. 





A balance puzzle 
20130114 

From Emily: I'm stuck on this problem and feel that it can't work! The problem is: there is a door with a balance scale on it. In order to open the door, you have to use the 5 weights to balance the scale. On the left side you have 2 boxes to place the weights and on the right side you have 3. You're 5 weights are as follows: 1lbs, 2lbs, 3lbs, 4lbs, 5lbs. How do you place the weights so that the scale is balanced? Answered by Penny Nom. 





The side lengths of a triangle 
20130107 

From Katie: How do I find the side lengths of a triangle knowing the base and its height?
Thank you, Answered by Penny Nom. 





A triangular island 
20121229 

From Udit: A long time ago Mr Gibson found an island shaped as a triangle with three straight shores of length 3 km,4 km and 5 km. He declared an 'exclusion zone' around his island and forbade anyone to come within 1 km of his shore. What was the area of his exclusion zone? Answered by Penny Nom. 





A 12 acre parcel of land 
20121228 

From John: What are the dimensions of a 12acre parcel if it is 3 square acres deep and 4 square acres wide? Answered by Penny Nom. 





Two polynomials are divisible by x  2 
20121226 

From Tehmas: Determine the values of m and n so that the polynomials 2x^3+mx^2+nx3 and x^33mx^2+2nx+4 are both divisible by x2. Answered by Penny Nom. 





The last 4 digits of a cell phone number 
20121222 

From Jacob: If the last 4 digits of a cell phone number, XXXXXXABCD, are restricted where: A cannot be 0 or 1 and B cannot be 0 / how many possible 4 digit combinations are left? Answered by Penny Nom. 





A project on reclaiming water 
20121211 

From shannon: I'm doing a report to reclaim water off of our campus facility to store in a cistern to use to flush toilets.
In Southeast Wisconsin and average of 82 inches of rain and snow fall annually.
I want to collect that off of the roof of our school building.
The roof is 37128 square feet.
how many gallons annually could I collect? Answered by Penny Nom. 





The angles of elevation and depression 
20121203 

From Chelsey: a person on a balcony of one building looks towards a second building. if the angle of elevation to the top of the second building is 25 degrees, the angle of depression to the bottom of the second building is 17 degrees, and the balcony of the first building is 22 feet above the ground, what is the height of the second building? Answered by Penny Nom. 





Transposition error 
20121203 

From Carol: What is the correct term for when a child writes 61 instead of 16, or 83 for 38when they switch the place values of a number? Answered by Chris Fisher. 





A function problem 
20121118 

From nahla: f: IN > IN
n > f(n)
for every n that belongs the IN : fof(x) = 4n  3
and for every n that belongs to IN f(2^n) = 2^(n+1) 1
Calculate f(993) Answered by Penny Nom. 





The square of any odd number, decreased by 1, is divisible by 8 
20121116 

From bailey: Prove that the square of any odd number, decreased by 1, is divisible by 8 Answered by Penny Nom. 





A mathematical expression with the answer 7 
20121110 

From emily: hey um i need to find and problem that fallows bedmas that has one division one multiplication and one sub and one add and one brackets and one exponents that has the answer of number 7 Answered by Penny Nom. 





Forming an algebraic expression 
20121027 

From ashley: A sidewalk has a constant width W and comprises several short sections having lengths
12, 14,and 10 feet. How do I find the simplified expression that gives the number of square feet of sidewalk? Answered by Penny Nom. 





Some 6 digit numbers 
20121023 

From Mason: How many different 6 digit numbers can you make using the digits 1 ,2 5, 6, 7, and 9? How many of these sixdigit numbers are divisible by 6? Answered by Penny Nom. 





A 2 acre plot 
20121022 

From bob: If a plot of land on the south side is 290.16 feet wide, how many feet on the west and east side to the north to make a 2 acre plot?
Thank You Bob Answered by Penny Nom. 





Converting a fraction to a decimal 
20121020 

From A Teacher: My students want an easy way to convert a fraction to a decimal, can I get one from you? Answered by Penny Nom. 





A proof by contraposition 
20121019 

From Rahul: I am not able to understand the following,
To prove that if for all e>0, x0, then x>=e. I understand the approach very well but I do not understand why if x=e then x>=e. If it is so then why not x=
Thanks in advance!'
Rahul. Answered by Penny Nom. 





Composition of functions and one to one 
20121017 

From Ariana: If f o g are one to one function,does it follow that g is one to one? Give reasons for your answers Answered by Penny Nom. 





A word problem involving a fraction 
20121012 

From Derrick: If the numerator and denominator of a fraction are both decreased by 1 the fraction becomes 2/3. If the numerator and denominator are both increased by 1 the fraction will be 3/4. Find the original fraction. How to do? Answered by Penny Nom. 





Find an algebraic expression 
20121003 

From Karen:
Question from Karen, a parent:
Find an algebraic expression relating the input and output.
input 
output 


3 
1 
9 
3 
15 
5 
21 
7 
27 
9 
Answered by Penny Nom. 





A problem involving simple interest 
20120927 

From Tash: The amount of money in a single year of an investment after P dollars were initially invested is A = P + Prt, where r is the rate of simple interest. What expression describes P? How much money was initially invested if the account has $1000 one year after the initial investment and the interest rate was 5%? Answered by Penny Nom. 





Changing the sign of an inequality 
20120919 

From Bryauna: Why do you change the signs in inequalities?! Answered by Penny Nom. 





The dimensions of a rectangle 
20120912 

From Becky: A rectangle has an area of 48 square inches and perimeter of 32 inches. Find the dimensions of the rectangle. Answered by Penny Nom. 





Six digit numbers 
20120911 

From Fiona: using the numerals 0, 2, 3, 5, 7, 9, make as many sixdigit numbers as you can. Rearrange them into ascending order Answered by Robert Dawson. 





Minutes and seconds 
20120829 

From Casey: I have to write a variable equation. The questions says there are 60 seconds. but we need to write and equation to solve for minutes. Is it 1/60 or 1/s Answered by Robert Dawson. 





Vector division 
20120828 

From Nazrul: If A and B be two vectors where B = 3 A The What is B/A ?
Please help me. Answered by Robert Dawson. 





An arithmetic progression 
20120822 

From A student: the 3rd term of an A.PPP is 10 more than the first term while the 5th term is 15 more than the second.find the sum of the 8th and 15th terms if the 7th term is 7 times the first term. Answered by Penny Nom. 





0.687 acres in square feet. 
20120718 

From Roy: The land parcel I am looking at says Acreage .687 how do I determine square feet? Answered by Robert Dawson. 





A sand box with 14 sides 
20120710 

From Tom: Want to build a sand box for a pool that is fourteen foot round wanted to make it in fourteen pieces of wood what angle would each piece be and how long would each piece be Answered by Harley Weston. 





Six people divided into three groups of two 
20120709 

From Fatima: Six people call them A,B,C,D,E,F are randomly divided into three groups of two,find the probability of the below event(do not impose unwanted ordering among groups)
E andF are in the same group
I solved it but I have a doubt that it is wrong .
My answer is 576
Please help to solve this problem. Answered by Lorraine Dame and Penny Nom. 





An octagonal sandbox around a pool 
20120612 

From Linda: My pool is 15 feet across and it is round.
How do I measure to cut wood to build a sandbox around it? was thinking it will look like an octagon.
Thanks Answered by Harley Weston. 





The position of an aircraft relative to the airport 
20120608 

From Dennis: "Air traffic controllers usually describe the position of an aircraft relative to the airport by altitude, horizontal distance, and bearing. Suppose an aircraft is at altitude 500m, distance 15km, and bearing 35 degrees east of north. What are the x,y, and z components (in meters) of the position vector. The xaxis is east, the yaxis is north and the zaxis is vertical. Answered by Penny Nom. 





Long division 
20120607 

From Emily: Simplify the expression using long division (9x^241x6)/(x4) Answered by Penny Nom. 





Division in base eleven 
20120527 

From Zoe: How do you divide numbers that are in base 11?
For example;
9A7A6A divided by A Answered by Penny Nom. 





cos(theta/30) = 1 
20120514 

From Hope: cos (theta / 30 = 1
I am very confused as to how to solve it. Can you help? Answered by Penny Nom. 





The dimensions of a rectangle 
20120430 

From Nikki: Name the dimensions of a rectangle that has the same area as this triangle?
I found the area of the triangle, which is 30. What do I have to do in order to complete this math problem? Answered by Penny Nom. 





Third side of a irregular triangle. 
20120427 

From Darya.: How to find third side of irregular triangle if c = 17m, b = 28m and area S = 210m^2. Answered by Penny Nom. 





How to find the base length of a isosceles triangle if only the sides are given? 
20120425 

From aqilah: how to find the base length of a isosceles triangle if only the sides are given? Answered by Chris Fisher. 





A rectangular prism 
20120405 

From Tori: How do you find the base height if the base width is 10ft. The height is 7ft. And the volume is105ft. Answered by Penny Nom. 





A uniform probability density function 
20120326 

From Noeline: The label on a bottle of liquid detergent shows contents to be 12 ounces per bottle. The production operation fills the bottle uniformly according to the following probability density function:
f(x) = 8 for 11.975 ≤ x ≤12.10
and
f(x) = 0 elsewhere
a. What is the probability that a bottle will be filled with 12.02 or more ounces?
b. What is the probability that a bottle will be filled between 12 and 12.05 ounces?
c. Quality control accepts production that is within .002 ounces of number of ounces shown on the container label. What is the probability that a bottle of this liquid detergent will fail to meet the quality control standard? Answered by Penny Nom. 





Forming a triangle from 3 line segments 
20120315 

From rustom: A point X is selected at random from a line segment AB with midpoint 0. Find the probability that the line segments AX, XB, and A0 can form a triangle. Answered by Penny Nom. 





The dimensions of a rectangle 
20120313 

From irvyn: if you are only given the area and the perimeter how do you find the dimension? Answered by Penny Nom. 





The dimensions of a conical tent 
20120304 

From yash: a conical tent is to accommodate 11 people.Each person must have 4m square of space on the ground and 20m cube at air to breathe.Find the height and radius of the conical tent.26202 Answered by Penny Nom. 





Integral 1/(25x^2)^3/2 
20120222 

From John: Integral 1/(25x^2)^3/2 Answered by Harley Weston. 





The 10000th day of her life 
20120221 

From derrick: Ella was born early in the morning on a Friday.She got married on the 10000th day of her life. What day of the week was it? Answered by Penny Nom. 





Simplify the expression 
20120212 

From Christy: Hi guys, ok so I'm having problems with solving this equation since it's been so long I've done precal.
I have to find critical points so I have to find the derivative first. This is what I've done so far
s(t)= (t6)^4 * (t+1)^2
t'= 4(t6)^3*(1)*(t+1)^2+ 2(t+1)(1)*(t6)^4
so this is where I got stuck, which is the algebra part. How can I simplify this to get the answer to figure out the critical points. Answered by Penny Nom. 





Litres in a box 
20120209 

From vicky: how much litre water can be filled in a box of 12 inches *24 inches *12inches Answered by Penny Nom. 





A tree growth modelled by a geometric series 
20120208 

From Steph: Hi I am really struggling with this question please help !!!!
a pohutukawa tree is 86 centimetres when it is planted. in the first year after it is planted , the tree grows 42 centimetres in height.Each year the tree grows in height by 95% of the growth of the previous year.
assume that the growth in height of the pohutukawa tree can be modelled by a geometric sequence.
A)find the height of the tree 5 years after it is planted and figure out the maximum height the pohutukawa tree is expected to reach in centimetres Answered by Penny Nom. 





The curvature of the earth 
20120208 

From sean: Question from sean, a student:
Two people 1.8 metres tall walk directly away from each other until they can no longer see each other (due to the curvature of the earth, which has a radius of about 6378 km).
A) Find a function relating the height of two identical objects with the distance between them using the scenario above as an example.
B) Sketch this function (you may use Graphmatica if you wish). Over what domain and range does the function exist?
C) Describe this relation in practical terms. Answered by Harley Weston. 





The dimensions of a rectangle 
20120131 

From Dazz: Hi I was wondering how to find the length of a rectangle if you know the area is 484 square inches And the length is 10 square inches or 22 square inches?
Thanks~Dazz Answered by Penny Nom. 





1 + 3 + 3^2 ...+3^(n1) = 3^n  1/2 
20120127 

From Vicki: I am trying to find out how to do show how this proof was worked.
Here is the end result 1 + 3 + 3^2 ...+3^(n1) = 3^n  1/2
This equation was used to find the number of white triangles in the Sierpinski Triangle Answered by Walter Whiteley. 





Tangent of theta 
20120117 

From stahl: explain what the 'tangent of theta' means. Draw and label a diagram to help with your explanation. Answered by Harley Weston. 





One acre of dirt 6 inches deep 
20120111 

From Cameron: Ok what im wanting to know is how many pounds of dirt are in 80
acres of land that is 6 inches deep? My friend and I are stumped on this question Answered by Penny Nom. 





The dimensions of a rectangle 
20120106 

From joseph: The perimeter of a rectangle is 72 inches. The length of the rectangle
is three more than 2 times the width of the rectangle. What is the
length of the rectangle? Write and solve an equation to determine the
dimension of the rectangle. Answered by Penny Nom. 





Limits and composition 
20111230 

From Rahul: I want to know about limit proofs of composite functions. Like limit of log of a function equals log of limit of the function Answered by Penny Nom. 





Three sides of a triangle 
20111224 

From saba: the three sides of a triangular lot have lengths 10,11and 13cm,respectively.
find the measure of its largest angle and the area of the lot? Answered by Penny Nom. 





The weight of 36 inch steel pipe 
20111222 

From Keith: What is the weight of 36 inch steel pipe 3/4 wall per foot in lbs. Answered by Penny Nom. 





i+i^2+i^3+i^4...+i^102 
20111213 

From megan: how do you solve i+i^2+i^3+i^4...+i^102 Answered by Robert Dawson. 





Simple interest 
20111211 

From sandeep: Use the formula I = Prt to solve.
Damon deposits $500 into a savings account that pays simple interest
at a rate of 0.65% per year. How long will it take Damon to earn $130
in interest? Answered by Penny Nom. 





Squares and triangles 
20111206 

From Liaqath: You have squares and triangles.
Altogether there are 33 sides.
How many squares do you have?
How many triangles do you have? Answered by Penny Nom. 





A suspension bridge 
20111130 

From jennifer: suspension bridges like the golden gate bridge, are used to span large distances.
when the main curved cables are attached to the deck by vertical cables they will end
up in the shape of parabola. assume that we need to build a bridge that spans
2,400 feet. the two towers 165feet tall each where placed at 400feet from either
side. the lowest point of the center of the bridge at 10feet. vertical suspension cables
where placed at 25foot interval. how many feet of cable are needed to connect
the deck to the main cables between the two towers? show all working. Answered by Penny Nom. 





The 3rd term of an A.P is 10 more than the first term 
20111129 

From Olaniyan: the 3rd term of an A.P is 10 more than the first term while the fifth term is 15 more than the second term. Find the sum of the 8th and 15th terms of the A.P if the if the 7th term is 7 times the first term. Answered by Penny Nom. 





Converting from base 4 to base 10 
20111129 

From anjg: How to convert base 4 number 2^11 to base 10 number? Answered by Penny Nom. 





An arithmetic expression 
20111128 

From Muhmmad: 2/5*3/71/6*3/2+1/14*2/5 Answered by Penny Nom. 





The LCM of 6,15 and x is 90 
20111030 

From Richie: Hi there,
There are 2 parts to the question.
#1. Factorise 90. This is easy, 90=2x3x3x5
#2
LCM of 6,15 and x is 90. What are possible values of x if x is odd?
From #1, since 90=6x15, how can this be used to work out possible values of x?
Thanks in advance,
Richie Answered by Penny Nom. 





A mythical soccer ball 
20111027 

From Joel: We've been working on this problem diligently and can't seem to come up with the answer book's answer. We think it may be wrong, yet want to check it with an expert. Here goes.
The school's new soccer balls are covered with 64 regular hexagonal panels. Each hexagon measures 2 inches between opposite corners and 1.5 inches between opposite sides. What is the total surface area of the soccer ball? Answered by Robert Dawson and Lorraine Dame. 





1 divided by 0 and infinity 
20111024 

From ritika: we say that one divided by zero gives us infinity, then why zero multiplied by infinity does not gives us one????????????? Answered by Robert Dawson. 





A 6% commission 
20111015 

From Tamara: if you earned a gross wage of $810, which includes a salary of $90 and a 6% commission how much is the net sales? Answered by Penny Nom. 





The sides of a regular octagon of area 800 sq. ft. 
20110921 

From Susan: Help please. I am building an octagon tree house to live in. I would
like the total square footage to equal 800 to 1,000 sq ft. How long
should each side of the octagon be.
tx, susan Answered by Penny Nom. 





A four digit number 
20110916 

From gina: i am having a hard time figuring this out.. i believe the answer is 3105 but the 0 is throwing me off... i am a 4 digit number between 3100 and 3200, none of my digits are even, the sum of my digits is 9, the largest digit is in the ones place, what number am i ?? Answered by Penny Nom. 





Composition of functions 
20110905 

From Jenna: Let f(x)=x^21 and g(x)=12x. Find the indicated values.
1. f(g(1)) and g(f(1))
Thanks,
Jenna Answered by Penny Nom. 





The dimension of the box in centimetres 
20110827 

From Eliza: Find the dimension of the box in centimetres. Then find its volume in cubic centimeters.
The box is 0.7m (l) 0.4 (h) 0.2 (w) Answered by Penny Nom. 





58 choose 4 
20110826 

From Jean: Using only the numbers 159, how many times would the
number 23 appear in combinations of 5 numbers?
... Can a list be provided as well?
Thank you very much,
Jean Answered by Penny Nom. 





A trapezoid 
20110802 

From Nazrul: How can I draw a trapezoid whose parallel sides and other two sides are given. Answered by Chris Fisher. 





The dimensions of a rectangle 
20110508 

From yolanda: If the length of a rectangle is 3ft less than twice its width and the area of the rectangle is 54ft^2,what are the dimensions of the rectangle? Answered by Penny Nom. 





The linear thermal expansion of steel 
20110503 

From Scot: Several questions on your site deal with the linear thermal expansion of steel. Such as how much will a piece of steel grow in length if it is heated. My question is similar but I would like to know if there is a different calculation to determine how much the diameter of a round bar will grow when heated. Can you tell me how I can calculate how the diameter of .500" round steel will increase for every degree of temperature change? If a bar is raised from 60 degrees F to 120 degrees F how much will the diameter change? Answered by Robert Dawson. 





An exclusion zone around a triangle II 
20110503 

From Aishwarya: A long time ago Mr gibson found an island shaped as a triangle with three straight shores of length 3km, 4km and 5km. He declared an exclusion zone around his island and forbade anyone to come within 1km of his shore. What was the area of his exclusion zone?
This question was answered but did not understand the explanation. Answered by Robert Dawson. 





(27^r^1)^2/3 
20110424 

From YungJu: (27^r^1)^2/3 Answered by Penny Nom. 





Decreasing numbers 
20110413 

From Hadi: A number is called a "decreasing number" if each digit in the number is less than the digit to its left.
For example, 87420 is a deceasing number. How many fivedigit
decreasing numbers are there? Answered by Claude Tardif. 





Eliminate y 
20110407 

From Lynn: 2x + y = 8
y + 3z =5
z + 2w =1
5w + 3x = 9
Form three equations with y eliminated Answered by Penny Nom. 





The rate of change of the area of a parallelogram 
20110405 

From Gevork: Let a parallelogram have sides of 8 and 12 and let vertex angle A be decreasing at a rate of 2degrees per minute. Find the rate of change of the area of the parallelogram when angle A equals 30 degrees. Answered by Penny Nom. 





Converting millimeters to centimeters 
20110404 

From Pat: I need to convert 67 mm to centimeters how do I do this? Answered by Penny Nom. 





3% commission 
20110401 

From bertha: A real estate brokers base annual salary is $18,000. She earns 3% commission on
total sales. How much must she sell in real estate value during the year to earn
$65,000? Set up an equation and solve. Show all work to receive full credit. Round
final answer to the nearest dollar. Answered by Penny Nom. 





The rectangle is reduced to 90% of its original size 
20110331 

From stephon: A rectangle has a length of 4cm and a width of 8cm.
If this rectangle is reduced to 90% of its original size what will be the new length Answered by Penny Nom. 





[(90+364) χ 2] x 15 = 
20110330 

From ken: [(90+364) χ 2] x 15 = Answered by Penny Nom. 





sin x = 0.25 
20110329 

From Wayne: How do you solve for x in the equation sin x = 0.25
the answer is 3.394 and 6.030 but I don't know the steps they used to calculate this Answered by Penny Nom. 





Write 3 1/5 in decimal form 
20110324 

From Stephenie: converting fractions????
3 1/5 into decimal??? Answered by Penny Nom. 





6(M1/9)=55/12 
20110315 

From Colleen: 6(M1/9)=55/12 Answered by Penny Nom. 





The mass of a metal box 
20110311 

From Pamela: A metal block has the dimensions of 3.16 inches wide, 2.15 inches
high, 4.98 inches long. What is the volume of the block in cm^3?
What is the block's mass if the metal has a density of 5.89g/cm^3. Answered by Robert Dawson. 





Vertices and sides of a polygon 
20110304 

From RINA: My questions is : would a vertices and sides of a polygon be the same number. For example, a octagon it has 8 points and 8 sides. Am i correct? Answered by Robert Dawson. 





Find the dimension of the original rectangle 
20110228 

From sandra: the perimeter of a rectangle is 40 cm. if the length were doubled and the width halved, the perimeter would be increased by 16cm. Find the dimension of the original rectangle Answered by Robert Dawson. 





A camera's line of sight 
20110226 

From MJ: A rocket that is rising vertically is being tracked by a ground level camera located 3 mi from the point of blast off when the rocket is 2 mi high its speed is 400mph At what rate is the (acute) angle between the horizontal and the camera's line of sight changing Answered by Penny Nom. 





Slicing a rectangular parallelepiped 
20110223 

From tom: a) Pass a plane containing a vertex of a rectangular parallelepiped and a
diagonal of a face not containing that vertex to cut a pyramid from the
parallelepiped. What fraction of the volume of the parallelepiped is the
volume of the pyramid thus cut off?
b)Pass a plane through a cube of edge 8 in so that the section formed
will be a regular hexagon. Through each side of the hexagon pass two
planes, one plane containing one of the two vertices of the cube
which are farthest away from the plane of the hexagon, the other
plane containing the diagonally opposite vertex of the cube. Find the
volume of the solid bounded by these planes.
c)three of the edges of a rectangular parallelepiped that meet in a point
are also the lateral edges of a pyramid. What fraction of the parallelepiped
is this pyramid...?
you know the my only problem is how to illustrate this one...if only i
could ...can you help me....all I need is the drawing and I can do the rest
..it's fine if you'll only answer any of these but I'll be thankful if you
will do the three :).... Answered by Penny Nom. 





Triangles with perimeter 16 cm 
20110222 

From Chong: How many triangles (up yo congruence) with perimeter 16 cm and whose lengths of its side are integers? Answered by Chris Fisher. 





Reversing the digits 
20110208 

From rejie: if the digits are reverse , the number is 9 less than the original number.what is the equation? Answered by Penny Nom. 





Calibrating a conical tank 
20110205 

From Bill: Hi, I have a round tank with tapered sides where I know the diameter at the top and bottom. Is there a formula I can use to calculate the volume by measuring from the bottom up the side (at the angle of the side) to any given point? Thanks, Bill Answered by Stephen La Rocque and Penny Nom. 





An even multiple of 27 
20110201 

From parth: the 6 digit # 63x904 is an even multiple of 27 what is X Answered by Penny Nom. 





The sides of an equilateral triangle 
20110127 

From Cristal: Hello :) How can i find the sides of an equilateral triangle when only given the height 10m? Answered by Penny Nom. 





Mathematics and a musical dilemma 
20110119 

From rahul: how is mathematics applied in entertainment? Answered by Harley Weston. 





2x = 2+2x 
20110115 

From james: 2x=2+2x can you help me find what x epauls? Answered by Penny Nom. 





The height of a lamp 
20110113 

From Dorothy: I need to find the lamp height with casting shadow (base line of triangle where a boy 1.6m tall stands 3m from base of street lamp and has a 2m shadow. In other words, think of a right angle triangle with zero height starting at left, then 2m to right stands boy (1.6m high). Angle (hypotenuse) increases up to top of street lamp with 'x' height and 3m base. Answered by Penny Nom. 





The weight of a tank 
20110111 

From tom: A tank, open at the top is made up of thin sheet iron 1in. thick. The internal
dimensions of the tank are 4 ft. 8in. in long ;3 ft. 6 in.in wide ;4ft 4 in. in deep
Find the weight of the tank when empty, and find the weight when full of salt
water. (Salt water weighs 64 lbs. per cu. ft., and iron is 7.2 times as heavy as
salt water) Answered by Harley Weston. 





Set notation 
20110110 

From Ron: The question asked in a handout:
8k  5 < 35, keI
I believe the answer to k is 5. But what does the k e(E) I mean in this? Answered by Harley Weston. 





The third side of a triangle 
20101228 

From andrea: in triangle abc, ab=5 and the area is 50cm2.If angle c 90degrees, find the length
of c. Answered by Penny Nom. 





The thermal expansion of steel 
20101220 

From roger: Knowing that the coefficient of thermal expansion of steel is 6.5E06
in/in/deg F. How do you calculate the loads applied as a result of the expansion? Answered by Robert Dawson. 





A geometric progression 
20101215 

From Abeth: find the value of x so that 2(x1), x+3, x will be a geometric progression. Answered by Penny Nom. 





The value after 30 years 
20101215 

From Abeth: At the end of every year, the owners of a building which costs 2, 500, 000 pesos deducts 15% from its carrying value as estimated at the beginning of the year. find the estimated value at the end of 30 years. Answered by Penny Nom. 





A rectangular solid 
20101208 

From ryan: Good day!
Have a question on rectangular solids. We were asked to find the dimensions of a rectangular solid, we were only given the volume of the rectangular solid, the total area, and the altitude. I tried using the volume of the rectangular solid and was able to get the area of the base, but I don't know how to get its length and its width. Hope you could help me again. Thanks! Answered by Penny Nom. 





Sales as a function of advertising 
20101208 

From Adori: The sales S(in thousands if units) of a product after x hundred dollars is spent on advertising is given by S=10(1e^kx). Find S as a function of x if 2500 units are sold when $500 is spent on advertising. Answered by Penny Nom. 





Simultaneous equations 
20101205 

From ryan:
Question from ryan, a student:
3 4
   = 1 (1)
x y
7 2 11
   =  (2)
x y 12 Answered by Chris Fisher and Stephen La Rocque. 





Simplify the logarithmic expression 
20101202 

From Adori: Use the properties of logarithms to simplify the logarithmic expression. Log(1/250) base 5 Answered by Penny Nom. 





How many gallons of water will it take to fill a classroom? 
20101201 

From deena: How many gallons of water will it take to fill a classroom that is 26 feet long by 19 feet wide and 9 feet high? How many tons of water will that be? Answered by Stephen La Rocque. 





Sides and diagonals of a polygon 
20101125 

From nicky: The sum of sides of two polygons is 12 and the sum of their diagonals is 19. What kind of polygon are they? Answered by Penny Nom. 





A remainder of 3 
20101124 

From khodr: find the smallest number (>3) that , when divided by 6 , 8 , 15 , and 18 , gives a remainder of 3 . Answered by Robert Dawson. 





Determine if a point is inside a cube 
20101124 

From Ali: hi every one
i have a problem with cube
they told me to write a program that determine if a point is
inside a cube
so i need the equation of the cube to do the comparison.
in sphere it is easy
sqrt((xxp)+(yyp)+(zzp))<=radios
if u please could help me Answered by Robert Dawson. 





A 20" octagon 
20101119 

From CHARLES: I have a 20" octagon and it has 8 parts. In inches how big is each
part. I was told each part was 5.86".The top of the octagon breaks
into 3 equal parts don't equal 20".When i did my math i thought it should be 6 5/8" which is closer
to 20"
I am trying to cut a octagon out of a 20"circle Answered by Stephen La Rocque. 





Simple interest 
20101117 

From Abeth: At what simple interest rate will a sum of money triple itself in 5 years time? Answered by Penny Nom. 





A six digit number containing no zeros 
20101115 

From John: Find a Six digit number containing no zeros in which the first digit is three less than the third,
the third digit is three less than the fifth,and the second digit equals the sum of the last three digits. Answered by Penny Nom. 





How far must the pitcher travel to get to the ball? 
20101104 

From ken: A baseball player bunts a ball down the first base line. It rolls 35ft at an angle of 26 degrees with the first base path. The pitchers mound is 60.5 ft from the plate. How far must he travel to get to the ball. Answered by Penny Nom. 





The sides of a trapezoid 
20101103 

From Bobbi: Isosceles Trapezoid base=60; two 45⁰angles at base, two 135⁰ angles at the top, vertical distance between base & top=16. What is the length of the top line and the two equal side lines? Answered by Penny Nom. 





The weight of some dirt 
20101103 

From Maggie: I am wanting to know how many tons of dirt we r going to need to fill a basement.
The measurements we r going with r 15ftx15ftx8ft. Answered by Penny Nom. 





I have a sign size regulation I have to meet. 
20101026 

From Scott: I have a sign size regulation I have to meet. The size is .6 meters squared. at first look this would be 2 ft x 2 ft.
I believe it would be larger then that. Can you confirm what the size would be in inches please. Answered by Penny Nom. 





a^(2^n) 
20101022 

From Tim: I am trying to understand a^(2^n).
The hint they give is a^(2^(n+1)) = (a^(2^n))^2
I am writing a program that will solve a^(2^n) recursively but need to
understand the power before I begin.
I am currently pursuing writing (a) x (a^(2^(n1))) where the
(a^(2^(n1))) would be the recursive function call a n approaches 0.
Once n is 0, the result would be multiplied by a two more times.
Anyway, explaining these powers would be appreciated. I will most likely
complete the program before the answer but I want to understand the
logic of these powers. Thank you, Tim Answered by Stephen La Rocque. 





Powers 
20101020 

From dylan: how do you write 20736 in exponential form .same for 1728 and 50625.
is there a formula to figure out how to express large know numbers in exponential form. Answered by Penny Nom. 





An exponential equation 
20101019 

From Sandi:
Question from sandi, a student:
I have several questions similar to this one and was wondering if you could walk me through this one. I'm totally lost on how to do it.
Paramecia reproduce by splitting in two. In a laboratory flask, a colony of paramecia had an initial population of 500. Each day, the population of the paramecia was counted. The results are as listed.
Time (in days)Population
0500
1600
2720
3864
41037
51244
61493
71792
82150
1.)Using graphing calculator make a scatter plot of the data in table.
I think I did this part right I set my window at Xmin=0 Xmax=10 Xscl=1 Ymin=0 Ymax=2500 Yscl=100 Xres=1
2.) Determine an exponential equation to represent the population as a function of time without using a graphing calculator.I have no clue how to do this.
3.)Suppose the flask and food supply is large enough to support the trend of the population growth. Estimate the population of the colony when the time is 10 days. Answered by Penny Nom. 





Simplifying fractions 
20101013 

From Alice: 14times (9divied3) + 12
______________________
18 divied (2624)
don't get this....... Answered by Penny Nom. 





Tiles on a bedroom floor 
20101007 

From Rochelle: John's bedroom floor is square in shape. He used 625 tiles, with a side length of 200 mm, to tile the whole floor.
Calculate the area and dimensions of the bedroom Answered by Penny Nom. 





A division sentence for an array 
20101005 

From Laura: On a math test Grace needs to look at an array and write a division sentence for the array. Grace writes 18/3=6 on her answer sheet. Describe what the array on Graces test looks like. Answered by Penny Nom. 





4√3 + 2√1/3 
20100925 

From Michelle: How do you solve 4√3 + 2√1/3? Please show step by step. Answered by Penny Nom. 





Six nines 
20100916 

From Steph: It's sort of one question. We have to use six nines to get the numbers 130. I got all but 22, 23, 24, and 30. Like 15 is 9+9(9+9+9)/9. Answered by Penny Nom. 





A building and a flag pole 
20100909 

From paul: A flag pole and a building stand on the same horizontal level. From the point p at the bottom of the building,the angle of elevation of the top t of the flag pole is 65 degrees. From the top q of the building the angle of elevation of the point t is 25 degrees.If the building is20 meters high. Calculate the distance pt Answered by Penny Nom. 





Disposing of some concrete 
20100812 

From Kathy: We are needing to dispose of concrete that we are tearing out of our
backyard and I need to figure the dimensions and weight.
I figured we have approx. 419 sq ft of concrete at 4" thick.
Could you tell me the how much that comes to in cubic ft,
cubic yards and weight. So I can get some estimates on pricing to
haul off and dispose of. thank you Answered by Harley Weston and Tyler Wood. 





A shrunken car 
20100731 

From Diana: Car manufacturers have outdone themselves. They have discovered how to shrink a car to make parking easier. At the touch of a button, a car shrinks by 2 feet in the width and 4 feet in the length. The original car base is 24 square feet longer than that of the shrunken car. If the original cars length is twice the width, find the dimensions of both cars. Identify the unknowns carefully. Answered by Penny Nom. 





70 cubic meters of mulch 
20100730 

From zsuzsi: i have 70 cubic meters of mulch to move and an 8 tonne truck to use
how much tonnage is to 1 square meter so that i can work out how many trips i need to make Answered by Penny Nom. 





The suspension cables of a bridge 
20100729 

From Mike: what is the formula for the suspension cables of a bridge.
The towers are 200 ft above the roadway
The towers are 3400 ft apart
The cable if at 8ft in the middle of the span Answered by Robert Dawson. 





The tonnage of some gravel 
20100722 

From Gregory: i have a road that is 8 miles long 20 feet wide and 4 inches deep what is the tonnage for gravel i would need Answered by Penny Nom. 





Simplify (2x)3 
20100716 

From emily: how to Simplify (2x)3 Answered by Melanie Tyrer and Penny Nom. 





Converting kilograms to cubic metres 
20100716 

From Ilai: I want to convert kg to cubic metre Answered by Penny Nom. 





The area of a 4 sided region 
20100714 

From Cliff: If I wanted to know the square footage of an area that has four different sides and only had the length of one side and the angles at the ends of that length; could the other lengths be found if I wanted to have a total of 130,680 square feet? Answered by Robert Dawson and Tyler Wood. 





Thermal expansion of a steel beam 
20100625 

From chris: If a 50 ft steel beam can expand up to 4inches when heated to 1000f
How much will a 162 ft and six inches steel beam expand under the same conditions? Answered by Robert Dawson. 





(x^3 + 11x) is divisible by 6 
20100624 

From PT: Given that x is a nonzero integer,
how do you show that for all values of x,
(x3 + 11x) is divisible by 6?
I know it works but how do I answer the "all values of x" part?
Thanks in advance! Answered by Robert Dawson. 





Expand and simplify 
20100615 

From Alaa: Expand and simplify
(x9)(x+2) Answered by Penny Nom. 





11 trillion divided by 309,418,000 
20100605 

From Dion: I am struggling to calculate what 11 trillion divided by 309,418,000 is. Answered by Penny Nom. 





The capilano suspension bridge 
20100603 

From nida: the capilano suspension bridge in north vancouver is the world's highest footbridge of its kind. the bridge is 140m long . from the ends of the bridge the angles of depression of a point on the river under the bridge are 41 degrees and 48 degrees. how high is the bridge above the river to the nearest metre Answered by Penny Nom. 





Math in the workplace: nursing 
20100524 

From Taylor: How is math used in the workplace  Nurse Anesthetist? Answered by Penny Nom. 





Divisibility by 3 
20100523 

From Cathleen: To math central. I have to do a maths extension question that I don't understand. At first I thought I did.
It is about the dividing by three. In one part of the question, it asks me to show that the rule of division by three does not work for 23142 with a little 5 down the bottom.
What doe base 5 mean? We first thought that the little 5 down the bottom meant multiplying y the power of five.
Can you please tell me what it means so I can finish this question? Answered by Penny Nom. 





converting y=mx+b into ax+by+c=0 and vice versa 
20100522 

From Paulo: converting y=mx+b into ax+by+c=0 and vice versa Answered by Tyler Wood. 





(x+1)(x+2)(x+3)/(x+1)(x+2) 
20100519 

From Nazrul: Simplify : (x+1)(x+2)(x+3)/(x+1)(x+2)
Which answer is correct:
(i) x+3
(ii) (x+2)^2(x+3)
Please help me. Answered by Harley Weston. 





A 22 litre bag of topsoil 
20100506 

From Blanche: I do a fair amount of gardening when the weather permits. Just wondered if anyone call tell me what a 22 litre bag of topsoil would weigh and how to convert that. My husband says 20 lbs. I say noway I think it's more. Thanks to whomever can help me. :) Answered by Penny Nom. 





Line of sight 
20100506 

From David: I live in St. Joseph, Michigan and there is an ongoing argument regarding lineofsight over the horizon.
Standing on a 200 foot high bluff here, people swear they can see the top of the Willis (nee Sears) Tower in Chicago, which is about 1653 feet high.
It is my contention that this is actually a "refracted reflection" and not directlineofsight.
So, to settle the argument, I'd sure like some simple explanation for this, even ifand I hope notI am incorrect.
David Answered by Harley Weston. 





Interest 
20100504 

From RW: If you earned 55.00 for a year in your savings acct. The account pays 0.5 % interest. How much money did you initially have in the savings account. Answered by Penny Nom. 





The rejection region 
20100501 

From Mong: In Tests of Hypothesis, what is the decision when the test statistic we compute from the sample information is exactly equal to the critical value? that is, we reject null hypothesis or do not reject it?
Thanks! Answered by Chris Fisher. 





A geometric progression 
20100430 

From Kalyani: sum of infinite geometric progression is 9 and common ratio is 1/10
then sum up to 8 terms is? Answered by Chris Fisher. 





Commission 
20100424 

From TAHIR: I want to predetermine the amount of commission on sale of my product which will be the amount that I shall have to pay .
For example, the price is $ 600and commission 5% .
1) I calculate commission on 600 @ 5% = $ 30
When added $ 600 the retail price = $ 630
2) But on $ 630, 5% commission = $ 31.50
So we make a loss of $ 1.50 .
3) Again if we add this $ 1.50 to $ 630 the price = 631.50
But the commission when calculated does not tally
and we make a loss of $ 0.075.
Please let me know how to determine the commission beforehand so that it matches our accounts. Answered by Penny Nom. 





4 + 10 + · · · + (6n − 2) 
20100421 

From Lan: Find the sum 4 + 10 + · · · + (6n − 2). The answer is 3(n^2) + n. How? Answered by Penny Nom. 





Four less than three times a number is 14 
20100416 

From David: My daughter has two questions that we could use some help with.
First ?
Four less than three times a number is 14
Secound?
The quotient of 15 and w Answered by Penny Nom. 





Polar coordinates 
20100414 

From Lan: Given the rectangular equation (x^2)+2x+(y^2)+y=0, find the polar equation. Answered by Harley Weston. 





Counting by sevens 
20100413 

From Larry: Lee counted by 7's beginning with one of the whole numbers from 1 through 7, until Lee passed 1000. If Lee counted
three of the following numbers, which number did Lee NOT count?
a. 107
b. 184
c. 534
d. 641
Answered by Robert Dawson and Penny Nom. 





6 items are taken 3 at a time 
20100412 

From Kristen: Explain the three different scenarios that could occur and would result in the following number of outcomes when 6 items are taken 3 at a time. Give reallife examples.
a. 63 = 6 x 6 x 6 = 216 possibilities
b. 6! / (6  3)! = 6 x 5 x 4 = 120 possibilities
c. 6! / (6  3)! 3! = 20 possibilities Answered by Tyler Wood. 





A cube with twice the volume 
20100411 

From Woojin: From a given cube create another cube with twice the volume.
the cube: 5cm each. Answered by Tyler Wood. 





Sample size 
20100329 

From Rae: What sample size was needed to obtain an error range of 2% if the following statement was made? "75% of the workers support the proposed benefit package. These results are considered accurate to within + or  2%, 18 out of 20 times. This seems like a straight forward question but I'm getting it wrong. Could you please help me out even just the set up would be appreciated so I can see if that's where I'm going wrong. Thanks Answered by Harley Weston. 





A radio tower 
20100326 

From Alex: The height of a radio tower is 450 feet, and the ground on one side of the tower slopes upward at an angle of 10 degrees. How long should a guy wire be if it is to connect to the top of the tower and be secured at a point on the sloped side 110 feet from the base of the tower? Answered by Harley Weston. 





What is 8.6597 divided by two thirds? 
20100322 

From patsy: what is 8.6597 divided by two thirds Answered by Penny Nom. 





A quadrilateral with 4 known sides and 1 known angle 
20100319 

From samuel: Name: Samuel
Status: Student
I have a quadrilateral with 4 known sides and 1 known angle, and I'm trying to evaluate the other angles of my quadrilateral.
By the law of cosines, I can easily find my opposite angle (using the diagonal as a basis for the equation).
However, to find the two remaining angles, I have found no other way so far than to use the other diagonal, which can be found with the equation attached (from geometry atlas).
Is there any simpler way? Answered by Robert Dawson and Harley Weston. 





How many zeros? 
20100318 

From jeff: 1 light yr is 6,500 billion miles, the galaxy "Andromeda" is 2,500,000 million light yrs, how many zeros are in this equation ? Answered by Robert Dawson. 





Repeating Decimal 
20100314 

From Gerald: Find the 1987th digit in the decimal equivalent to 1785/9999 starting from decimal point. Can you give us a short but powerful technique in solving this problem? thanks so much.. Answered by Chris Fisher. 





A 14 side well house cover 
20100312 

From Kenneth: I am 35 yr I am wanting to build a well house cover. I'm trying to figure out how long the pieces need to be and what angle they need to be for a 4 ft dia with 14 side well house. I would love an answer but would also like to know how to figure it in the future. Thanks Kd Answered by Harley Weston. 





The nth derivative of x^(n1) log x 
20100310 

From shambodeb: This is a successive differentiation problem by Leibnitz theorem
If y = x^{n1} log x ; Proof nth derivative y^{(n)} = (n1)!/x Answered by Harley Weston. 





The side length of a square 
20100308 

From tara: am trying to help my brother's daughter in maths, tomorrow she has maths exam
1. Area of sq. picture is 441 sq.cm what is the length of its side. Answered by Penny Nom. 





0.999 ^ (500) 
20100307 

From debra: I just need to know how to solve the following problem without using a calculator: .999 ^ (500). I know the answer is .606, I just want to do it by hand since I can't use a calculator on my test. Answered by Penny Nom and Claude Tardif. 





The dimensions of a rectangle 
20100303 

From Kirsten: A rectangle is twice as long as it is wide. Its area is 128 square meters. What are the dimensions of the rectangle? Answered by Tyler Wood. 





The test for some disease is 99% accurate 
20100224 

From baaba: Assume that the test for some disease is 99% accurate. If somebody tests positive for that disease, is there a 99% chance that they have the disease? Answered by Chris Fisher. 





Fahrenheit and celcius 
20100219 

From Carol: Zack is packing for a trip to Scotland. He read that the average temperature in the Summer is 18degrees C during the day, and 7 degrees during the night. What is the difference between the high and low temperatures in degrees Fahrenheit? (F=9/5C=32) Answered by Lorraine Dame. 





Square poles 
20100216 

From Steve: If 1 pole=16.5', and you have an area that is 146 sq. poles, how many sqaure feet would you have?
I calculate that to be 146(16.5)X146(16.5)=5,803,281 sq. feet Is that correct? I am told I need to divide by 146, which makes the answer 39,748. I do not understand why I need to divide by 146.... Answered by Penny Nom. 





4digit positive numbers 
20100215 

From marjon: Find the sum of all the 4digit positive numbers with no zero digit. Answered by Penny Nom. 





The dimensions of a flag 
20100215 

From dawn: a state flag was twice as long as it was wide and had an area of 288 sq inches, what were its, dimensions
Thanks Answered by Penny Nom. 





The difference of the two numbers 
20100215 

From Steve: The difference of the two numbers 'abcdef ' and ' fdebca ' is divisible by 271. prove
that b = d and c = e. Answered by Claude Tardif. 





Can a line segment curve over two planes? 
20100214 

From Graham: I am working on a math fair project.
Can a line segment curve over two planes?
Such as, if I had a three dimensional L bracket and I drew a line segment
on it with a marker starting on the bottom of the L and had it curve
around the corner and up the top, would it still be considered one line
segment? Or is that two line segments?
Is there a rule that a line segment can only occupy one plane?
Thank you.
Graham Answered by Chris Fisher. 





A sequence 
20100207 

From Shalev: hi,
i had a job interview yesterday. it had mathematical questions. couldn't solve 1. i m obsessed with it. please find out what the answer is..
it goes like this:
2,4,5,5,8,6,_,_,14,8
thank u very much Answered by Claude Tardif. 





I want to convert my glaze percents into grams 
20100205 

From linda: I am a potter. I want to convert my glaze percents into grams.
ex. 20% of 20 lbs would equal how many grams?
is there a formula to figure this? Answered by Penny Nom. 





An impossible isosceles triangle 
20100131 

From Hailey: An isosceles triangle has one angle that measures 50 degrees and another that measures 70 degrees. Why can't this triangle be drawn? Answered by Penny Nom. 





Solving a triangle 
20100125 

From Paige: how do i solve a triangle with one angle of 73 degrees,
one angle of 32 degrees, and one side of 23cm? Answered by Harley Weston. 





A sequence 
20100122 

From brahmaji: 0 7 26 63 _ 215 342 fill the blank? find the missing number Answered by Robert Dawson. 





The volume of a silo 
20100121 

From heather: The height of the silo is 30ft and the face that rests against a barn is 10 ft wide. If the barn if 5 ft from the center of the silo what is the capacity of the silo? Answered by Penny Nom. 





Area in square meters 
20100120 

From Carla: A football field is 120 yd long and 50 yd wide. What is the area of the football field, in square meters? Answered by Penny Nom. 





How fast am I walking? 
20100110 

From KEVIN: IF I WALK 3 MILES IN 28 MINUTES, HOW FAST AM I WALKING? Answered by Penny Nom. 





The intervals where the function is positive and negative 
20100110 

From Ron: Hello
I'm trying to find out the intervals where the function is positive and negative.
It's for a polynomial function y= (x+2)^2 (x2) and y= (x+1)(x+4)(x3)
I have tried the right and left side of each xintercepts, but I still don't understand the
results
thank you for your help Answered by Penny Nom. 





A pair of simultaneous equations 
20100109 

From Yumiko: Solve the following pair of simultaneous equations.
x^2 4x = y^24
3y=2x  3 Answered by Penny Nom. 





Linear programming using the Simplex Method 
20091228 

From William: A gold processor has two sources of gold ore, source A and source B. In order to keep his plant running,
at least three tons of ore must be processed each day. Ore from source A costs $20 per ton to
process, and ore from source B costs $10 per ton to process. Costs must be kept to less than $80 per day.
Moreover, Federal Regulations require that the amount of ore from source B cannot exceed twice the
amount of ore from source A. If ore from source A yields 2 oz. of gold per ton, and ore from source B
yields 3 oz. of gold per ton, how many tons of ore from both sources must be processed each day to
maximize the amount of gold extracted subject to the above constraints?
I need a linear programming solution or algorithm of the simplex method solution.
Not a graphical solution. Thanks. Answered by Janice Cotcher. 





StefanBoltzmann Law 
20091228 

From florence: Hi
I have a college tutor and we are stumped with this question.
Assuming a filament in a 100 W light bulb acts like a perfect blackbody, what is the temperature of the hottest portion of the filament if it has a surface area of 6.3 X 10^5 m^2? The StefanBoltzmann constant is 5.67 X 104 W/(m^2 X K^2.\
Thank you for your help. If you can only answer one question per day please answer this one and guide me through a solution. Answered by Janice Cotcher. 





Finding Density Given Volumetric Thermal Expansion Coefficient 
20091226 

From florence: Hi
Please help me to apply the formula for this problem. The coefficient of volumetric for gold is 4.20 X 10^5 C degrees. The density of gold is 19,300 kg/m^3 at 0.9 C degrees. What is the density of gold at 1050 degrees C.
Could you please explain how to get the solution of 18,500 kg/m^3
Thank you for your help
Florence Answered by Janice Cotcher. 





Triangles on a base of 2.4 meters 
20091226 

From Allan: Please,How do I calculate the height of a triangle when I only know the width of the base line,It is 2.4 mtrs. Thankyou very much. Answered by Penny Nom. 





Finding Specific Heat of a Substance 
20091226 

From erin: Hi
2 kg metal requires 1.00 X 10^4 J of heat to raise its temperature from 20 degrees C to 40 degrees C. What is the specific heat capacity of the metal? Answered by Janice Cotcher. 





A trig question 
20091215 

From A trig question: Hey, my name is Candle
I'm in academic math10 and am stuck on my trig... one question I thought I had right because i used the cosine law I got wrong and can't figure out why... here's a copy of the question. (i guessed it was D... but my teacher said it's B)
Thanks
Candle Answered by Robert Dawson. 





Energy in calories 
20091215 

From Josephine: A soft drink manufacturer claims that a new diet soft drink is now "low Joule". The label indicates that the available energy per serving is 6300 J. What is the equivalent of this energy in calories? (1 Calorie=1000 cal) Answered by Robert Dawson. 





A telephone pole on a slope 
20091214 

From Marissa: A 10 meter telephone pole casts a 17 meter shadow directly down a slope when the angle of elevation of the sun is 42 degrees. Find the angle of elevation of the ground. Its a law of sines problem. Answered by Penny Nom. 





A number base that's not a positive integer 
20091211 

From Nick: Is it possible for a number to have a base that's not a positive integer?
Base 1 gives a result that's meaningless but possible. I have no concept of a base 0, a negative base, or a fractional base, never mind any other base. I think there isn't any base that's not a positive integer, but, knowing that math keeps jumping ahead and sometimes has inventions before anyone knows how to exploit them, I think I'd better ask.
Thank you.
Nick Answered by Robert Dawson and Claude Tardif. 





How fast is the distance between the two cars decreasing? 
20091208 

From Jenny: Two cares are on a collision course toward point P. The paths of the two cars make a 30 degree angle with each other. The first car is 40 km from P, and traveling toward P at 16 km/hour. The second car is 50 km from P, traveling at 20 km/hour. How fast is the (straight line) distance between the two cars decreasing. (Hint: Law of Cosines) Answered by Harley Weston. 





Simplifying a quadratic expression 
20091207 

From Sabbie: Hi, I need help solving this equation for my physics homework,so I can solve the quadratic equations for x and y.
I've derived the following equations from the information provided in the question.
2a+3b = 4  1
2a^2 + 3b^2 = 62  2
a=2(3/2)b is substituted into equation 2.
so, i get
2 (2(3/2)b)^2 + 3b^2 = 62
this is where the problem begins. i cannot work through this to get to the correct quadratic equation
5b^28b36=0
I can't seem to be able to figure out where I keep going wrong. I would really appreciate it if you could give me a stepbystep breakdown of the workout.
thanks! Answered by Penny Nom. 





(9  x^2)/(x  3) 
20091204 

From Sandy: 9x^2/x3
I need to know how to solve this.
Thanks Answered by Penny Nom. 





Milliliter conversion 
20091129 

From Jan: I am trying out a new bath salt recipe for one of my clients that has little children. Here then is the question, the recipe for color changing bubble bath calls for 0.15ml dry FD&C color. Since the recipe came from Australia, I have not a clue of how to change this into USA measurments Answered by Penny Nom. 





Sixletter words 
20091124 

From christine: How many sixletter words (not necessarily an English words) are there in which exactly three of the letters are z's? Answered by Claude Tardif. 





Solving two equations, one with a square root 
20091123 

From kacie: y = square root of x+3
x4y = 7
im having trouble with this problem...i have to find where they intersect. Answered by Harley Weston. 





A simplification 
20091121 

From Lou: In the following problem, [(7)/(x+2)][(x+8)/(4x^2)]+[(3x2)/44x+x^2)]
what steps do you use to convert the middle portion to become +[(x+8)/(4+x^2)]?
The answer to the problem is supposed to be (11x^218x+8)/(x+2)(x2)^2 Answered by Penny Nom. 





Three angles and one side of a triangle 
20091116 

From Esther: How do i find the sides of an acute triangle if i know the angels are 60,45,75 and i only know one side which is 10? Thanks! Answered by Penny Nom. 





Two similar pentagons 
20091116 

From louis: The lengths of five sides of a pentagon are 1,3,5,7,and 12 units. If the length of the longest side of a similar polygon is 18 units, find the perimeter of the larger pentagon. I think I figured it out Not sure though. Answered by Penny Nom. 





The line through D(4, 0) and E(2, 6) 
20091116 

From Rogerson: The point F is on the line through D(4, 0) and E(2, 6) so that DF=4DE. Find the coordinates of F. Answered by Penny Nom. 





A drawing of a baseball diamond 
20091109 

From Beth: My husband has a drawn diagram on a piece of paper of a baseball diamond. He knows that on the paper 1 1/16" (1.6875") = 90 actual feet. How do we calculate how many feet 5 7/8" on the paper would be? Answered by Penny Nom. 





3x^33x3 and 3x+6 
20091104 

From spencer: My question is 3x^33x3 devided by 3x+6 Answered by Penny Nom. 





Density of dirt and gravel 
20091026 

From ken: if digging a load of dirt and gravel in mining how many yards of material to the ton thanks Answered by Penny Nom. 





Grams per square meter 
20090930 

From MANISH: how to calculate gsm given kg of 144 sheets and size in inches
example 28" x 22" & 16.3 kgs = ?gsm (of 144 sheets) Answered by Penny Nom. 





Sawdust 
20090929 

From joel: What is the density of saw dust Answered by Harley Weston. 





Grams to percent 
20090920 

From brandy: how do you convert 1.5 grams to a percent Answered by Stephen La Rocque. 





A sequence 
20090919 

From Oliver: I am struggling to work out the missing terms in the following sequence:
1, 3, _, 7, 11, 18, _ Answered by Chris Fisher. 





Repeating decimal to fraction 
20090918 

From joan: how can i answer it easily to convert terminating decimal to fraction?
example of this is that, convert ...143143143... to fractional form Answered by Robert Dawson. 





Quotient 
20090914 

From Jala: What is a quotient and what are the instructions for one? Answered by Penny Nom. 





Simplify 
20090904 

From Sarah: How do you simplify:
(x4)^3? Answered by Robert Dawson. 





Simultaneous equations 
20090828 

From onias: solve 3/a  2/b = 1/2 , 5/a + 3/b = 29/12 Answered by Robert Dawson. 





How do you convert cents/mile to dollars / hour? 
20090826 

From seanna: how do you convert cents/mile to dollars / hour Answered by Penny Nom. 





A paper towel roll 
20090819 

From Jeff: I am making a spiral tube with paper that is 2" in dia. and 102" long
I will be using paper that is slit 3" wide how many lineal feet of paper will
I need to to cover the 102"
I will be using 3 rolls of paper that will over lap the other by half to make
a hard tube (paper core) in a roll of paper towels
Thanks Jeff Answered by Penny Nom. 





How do i convert 6 feet into yards? 
20090814 

From taylor: how do i convert 6 feet into yards????????????????? Answered by Robert Dawson. 





Fitting the curve y=a*exp(b*x)+c 
20090812 

From aika: Could one show me the complete algorithm and formula for finding the coefficients (a,b, and c) in exponential regression model
y=a*exp(b*x)+c Answered by Robert Dawson. 





Gravel in an aquarium 
20090809 

From Bev: Hi...I worked this part out, but want to know how many kilograms of gravel I will need...thanks
Bev
Cylinder shape.
A cylindrical shape that has a radius of 82 centimeters and a depth of 7 centimeters has a volume of:
Volume
= 0.14787 cubic meters
= 147870 cubic centimeters
= 0.1934 cubic yards
= 5.2219 cubic feet
= 9023.5 cubic inches
= 39.063 U.S. gallons
= 147.87 liters
* calculations accurate to 5 decimal places of precision Answered by Harley Weston. 





Eye Height Level Found from Visual Angle 
20090807 

From Jolie: Hello,
I am trying to figure out what height from the ground a person's eyes are if they have a 12 degree visual angle to a screen that is 58cm away from their eyes?
Thank you. Answered by Janice Cotcher. 





Dimensions 
20090729 

From Deborah: The blueprint for landscaping a yard has a scale of 1/2" to 1 foot. If the blueprint is a rectangle 18 inches by 22 inches, what are the dimensions of the yard? Answered by Robert Dawson. 





x^3+1/x^3=18*sqrt(3) 
20090708 

From Nazrul: If x^3+1/x^3=18*sqrt(3) then how can I evaluate the value of x+1/x?
Thank you for your help. Answered by Robert Dawson. 





The sides of a triangle 
20090708 

From Susan: The second side of a triangle is 5ft more than the length of the first side. The third side of the triangle is 10ft less than the length of the first side.
The perimeter of the triangle is 61ft. Find the lengths of each side of the triangle.
Thank you so much! Answered by Penny Nom. 





Simultaneous Equations 
20090706 

From Mukulu: Solve the equation simultaneously X/5=(Y+2)/2= (Z1)/4
.eqt 1
3X+4Y+2Z25=0
eqt 2 Answered by Janice Cotcher. 





Coefficient thermal expansion of steel 
20090629 

From roshni: Coefficient thermal expansion of steel is 0.00000645/in/in/deg F if F was C(celcius) then what is the answer Answered by Robert Dawson. 





The dimensions of a cuboid 
20090624 

From laura: a cuboid has the surface area of 842 cm2, can you work out the dimensions? Answered by Robert Dawson and Harley Weston. 





Cubic meters of gravel in a 7 ton lorry 
20090621 

From Jackie: I have to transport gravel in a 7 ton lorry and I know how many cubic meters of gravel I need, but I need to know how many cubic meters of gravel a 7 ton lorry can hold.
Thanks, Jackie Answered by Penny Nom. 





Two questions from math class 
20090618 

From Con: Hello,
My name is Con and my son is required to answer the following questions for his maths class.
He has attempted Q1 through trial and error and has found the answer to 72453. Is this correct?
He has attempted to draw the triangles described in Q2 in a number of ways and has found that BE can not equal ED and is dependent of angle BAC. Therefore, he claims that the triangle can not be drawn/practical. Is this correct or is there a slolution?
Q1.
Digits 2, 3, 4, 5 and 7 are each used once to compose a 5digit number abcde such that 4 divides a 3digit number abc, 5 divides a 3digit number bcd and 3 divides a 3digit number cde. Find the 5digit number abcde.
Q2.
Let ABC be a triangle with AB=AC. D is a point on AC such that BC=BD. E is a point on AB such that BE = ED = AD. Find the size of the angle EAD.
Con Answered by Chris Fisher. 





Successive differences 
20090618 

From Jonathan: I'm trying to find the next number sequence for this equation: 1 11 35 79 149 251, my problem is that I worked it out and ended up with a single number 17. What am I doing wrong. Thank you for any help. Answered by Robert Dawson and Penny Nom. 





Thermal Expansion of Steel 
20090617 

From Ken: Hi there, We are rollforming steel roofsheeting in 65M lengths and the =
question of linear expansion has cropped up.I would like to know what =
the expansion rate of this sheet would be over a temperature rise of say =
40degree F.in mm per Meter or whatever the norm is. The sheet is 0.53mm =
thick and is 700mm in width,I hope this is sufficient info to enable you =
to do your calculation.Many thanks, in anticipation.
Ken Answered by Janice Cotcher. 





Divisibility 
20090617 

From Sophia: Hello
Please help my son with the solutions to the following:
a) Determine the remainder when 2^2009 + 1 is divided by 17;
b) Prove that 30^99 + 61^100 is divisible by 31;
c) It is known that numbers p and 8p^2+1 are primes. Find p.
Again, your assistance is greatly appreciated.
Thanks
Sophia Answered by Robert Dawson. 





Vectors and the Law of Cosine 
20090608 

From lauren: once force of 20 pounds and one force of 15 pounds act on a body at the same point so that the resultant force is 19 pounds. Find, to the nearest degree, the angle between the two original forces Answered by Janice Cotcher. 





Initial Velocity of a Car Plunging Off a Cliff 
20090607 

From Mimi: A car fails to take a sharp turn on a flat road and plunges off a cliff. The car lands 65m horizontally and 43m vertically from where it left the edge of the cliff. How fast was the car travelling? Answered by Stephen La Rocque. 





The dimensions of a rectangle 
20090530 

From Linda: A rectangle has a perimeter of 38 feet & an area of 48 square feet. What are the dimensions of the rectangle? Answered by Stephen La Rocque. 





A sequence 
20090526 

From Jay: what is the equation that would give me the next 3 numbers in this progession: 0,1,5,14,20 Answered by Stephen La Rocque. 





The quotient of 5/8 divided by7/4 
20090525 

From tammy: find the quotient of 5/8 divided by7/4 Answered by Stephen La Rocque. 





The Smythe family lot 
20090524 

From Shrima: We must determine the size of the lot. The Smythe family lot is 235ft
across the front and 212ft down the side and 254ft down the other side.
The sides of the lot are parallel to each other and perpendicular to the front.
The size of the lot is two dimensional measure therefore you need to find
the areaenclosed by the lot line.
Question:
What is the size of the Smythe lot including the unit? Answered by Penny Nom. 





The position of the fulcrum 
20090523 

From jim: I think I need a formula. I need to know how far an object will be lifted.
A beam is 246 inches long on one side of the fulcrum, and 41 inches on the other side,
if I push down 36 inches on the long side of the beam, how much will the short side move up? Answered by Stephen La Rocque. 





A geometric progression 
20090516 

From sweta: find the ratio of GP if the first term is 1 and the sum of third and fifth term is 90. Answered by Penny Nom. 





Unit Conversion for Force and Mass 
20090508 

From Ray: Good Day! I was confused about lbm and lbf and slug. I knew that lbm is a unit
for mass and lbf is a unit for weight. my problem is some books follow this
relationship where lbf=(lbm times the gravitational pull) which is 32.2 ft/(s^2)
while other books treat lbm=lbf. other books also treat lbm=(lbf times 32.2)...
which is correct?
Is 1kg=2.205 lbm or 1kg=2.205lbf?
Is 1BTU=778.16 lbfft or 1BTU=778.16 lbmft?
what is the relationship of slug on these two, lbm and lbf? Answered by Janice Cotcher. 





Cubic feet and cubic yards 
20090508 

From TJ: 21 bags at 2 cubic feet per bag.
How many yards would that be? Answered by Penny Nom. 





The dimensions of a toy chest 
20090507 

From charlotta: My son needs to find the 3 dimensions of a toy chest that has to have a volume of 24 cubic feet can you show how to get the answer Answered by Penny Nom. 





8.55 acre of land 
20090506 

From Mary: I have a deed with 8.55 acre of land, how much land is that .55 ? Answered by Robert Dawson. 





5^2= 25 
20090506 

From tracy: show how to perform this calculation and why
5^2= 25 Answered by Robert Dawson. 





How do you convert 1248 to base 6? 
20090502 

From Tamara: How do you convert 1248 to base 6? Answered by Penny Nom. 





Decimeters and centimeters 
20090430 

From Jeannette: I cannot convert because of a question that throws me off. For example, A mother African elephant avg's 250 dm in height. A newborn baby African elephant avg's 89cm in height. How many cm shorter is the baby African elephant than its mother? Which one do I convert first? in order to subtract the number from the baby? Answered by Penny Nom. 





The volume of 3D figures 
20090429 

From Serena: What is the formula for finding the volume of 3D figures Answered by Robert Dawson. 





The integral of a to power x squared 
20090428 

From JIM: WHEN I ATTENDED U.OF T. (TORONTO ) MANY YEARS AGO
WE WERE TOLD THE FOLLOWING INTEGRAL COULD NOT BE
SOLVED : a to power x squared . is this still true ?
CURIOUS , JIM Answered by Robert Dawson. 





An odd shaped lot with a curve to it 
20090425 

From Chris: Hi  Im trying out to figure out how to calculate the size of an odd shaped lot with a curve to it.
Chris Answered by Harley Weston. 





2+6+12+20+30+42 
20090424 

From fredy: what is the sigma notation for the series 2+6+12+20+30+42? Answered by Stephen La Rocque. 





Miles per hour and feet per second 
20090422 

From mary: A car traveling at 60 miles per hour, how many feet per second has it traveled? Answered by Robert Dawson. 





Percent increase from a negative number to a positive number 
20090421 

From Brian: I have no problem calculating year over year net profits but am having trouble when it comes to a negative.
2007 Net Profit = 110,333.00
2008 Net Profit = 66,054.00
Brian Answered by Harley Weston. 





Two regular hexagons 
20090421 

From niko: Two regular hexagons are ____________ similar. Answered by Stephen La Rocque. 





Two similar rectangles 
20090419 

From Alyssa: The ratio of the lengths of corresponding sides of two similar rectangles is 3:5. the small rectangle has an area of 36 square centimeters. What is the are of the large rectangle? Answered by Penny Nom. 





A foursided lot 
20090412 

From Robert: back of property is 137' across,with an angle of 122deg.on the left side and an angle of 140 deg. on the right side,the left side is 123' and the right side is 93' long,the left front is 130 deg. and the right front side is 150 deg. and the front of the property measures 78' Answered by Harley Weston. 





A fraction in its simplest form 
20090402 

From Michael: I'm in 4th grade and need to express decimals as a fraction in its simplest
form. Is there a step by step method to figure out?
ex 0.64 = 64/100 = ? Answered by Robert Dawson. 





Thirtytwo divided by 3 
20090402 

From Shelly: x = 32/3
x = 10 2/3 Divide 32 by 3: 32 / 3 = 10 R2.
What I don't get is why is it that 10 with a remainder of 2 ( 10 R2 ) equals 10 2/3? shouldn't it be 10 2/10 ????? Answered by Robert Dawson. 





A spherical Tootsie Roll Pop 
20090401 

From Tracy: A spherical Tootsie Roll Pop you are sucking on is giving up volume at a steady rate of .8 ml/min. How fast will the radius be decreasing when the Tootsie Roll Pop is 20 mm across? Answered by Harley Weston. 





Four identical lots 
20090330 

From Marina: I really want to know the answer to this problem for my 6th grade son. I've already sent this question with the drawing but I couldn't send it correctly. I hope this one will pass through.
Q: Divide evenly and identical the figure representing a lot, into four for the 4 siblings. I've sent a figure drawing as attachment. I will describe this in case it will not reach you: its a square divide into 4 triangle and 1 triangle is taken out living a letter M figure and
this letter M figure is the one that will be divided.into 4 even and identical parts.
Marina Answered by Claude Tardif. 





Adding in base six 
20090329 

From Lucy: If you are working in base 6,
what do you have to add to 4(base 6) to get 10(base 6)???? Answered by Penny Nom. 





Subdividing a foursided lot 
20090327 

From kannan: i have a 1.5 acre land having four sides
AB=64.8 meters
BC=94.2 meters
CD=54.4 meters
DA=127.2 meters
angle at D is 90
the side AB (frontage)is road facing i want to split the plot in to two halves
having same almost area and almost equal frontage, kindly help me, if possible
explain with drawing.
Regards
Kannan Answered by Harley Weston. 





Dividing by fractions 
20090325 

From Mitch: 2 divided by 2/3 = ?? Answered by Penny Nom. 





Comparing positive and negative fractions 
20090324 

From Christyrose: Hello. I am a sixth grade math student and i need help on how to compare negative and positive fractions.
Here is is:
3/4 2/3 7/10 5/6
I'm not sure how to do the negative parts because i was absent for a couple days. Thank you!
Christyrose Answered by Penny Nom. 





Conversion factor 
20090323 

From kab: Would like to photocopy a Landscape Design. What is the Conversion Ratio or magnification required to convert 1" = 10 feet to 1/4" = 1 foot? Answered by Harley Weston. 





A rectangular open box 
20090321 

From tina: An open box is to be made from a rectangular piece of tin by cutting two inches squares out of the corners and folding up the sides. The volume of the box will be 100 cubic inches. Find the dimensions of the rectangular piece of tin. Answered by Stephen La Rocque. 





A 20 foot piece of pipe 
20090319 

From chris: How many 8 inch pieces can you get from a 20 ft. piece of pipe? Answered by Penny Nom. 





0.0007 as a percent 
20090318 

From Shelly: I need to know how to divide 0007 by 100 and soon! and I have no idea how I can get 100 to go into a number like that! here's the question this problem originated from:
change the decimal into a percent:
0.0007 _________
How do I change THAT number into a percent?
How do I change 12.455 and 92.348 and 29.005 into percents as well? I know how to change numbers like 0.6 and 0.70 into percents but not the numbers I told you I'm having problems with. Please someone explain this to me and also please focus mainly on the first number I asked about but don't forget the others please. Please reply ASAP I need to know this in about a week or less! Answered by Penny Nom. 





The sides of a parallelogram 
20090317 

From Sami: If ABCD is a parallelogram, prove that line AB is congruent to line CD. Clearly state your reasons and conjectures. Answered by Penny Nom. 





An impossible trig problem 
20090314 

From Alisha: If csc theta = 3 and sec theta = square root of 3, what are the values of tan theta and cos^2 theta? Answered by Harley Weston. 





Related rates 
20090314 

From Jeevitha: The side of an equilateral triangle decreases at the rate of 2 cm/s.
At what rate is the area decreasing when the area is 100cm^2? Answered by Stephen La Rocque. 





A polyhedron 
20090310 

From Mollie: Hi, my name is Mollie and I'm in 5th grade. Here's the math problem I have for homework tonight:
"Larissa made a model of a polyhedron using 8 pieces of clay for the vertices and 18 straws for the edges. What type of
polyhedron did Larissa make?"
Thanks. Answered by Penny Nom. 





Related rates 
20090309 

From Megan: A plane flying with a constant speed of 330 km/h passes over a ground radar station at an altitude of 3 km and climbs at an angle of 30°. At what rate is the distance from the plane to the radar station increasing a minute later? Answered by Harley Weston. 





What percent commission does Aaron earn? 
20090309 

From Jerry: Aaron works part time as a salesperson for an electronics store. He earns $4.75 per hour plus a percent commission on all of his sales. Last week Aaron worked 20 hours and earned a gross income of $143.75. If his total sales for the week were $1,500, what percent commission does Aaron earn? Answered by Penny Nom. 





The sides of a triangle 
20090307 

From felicia: ona map, tannersville, chadwick, and barkersvile for a triangle. Chadwick is
70 miles from Tannersville and Barkersville is 90 miles from Tannersville. Which is a
possible distance between Chadwick and Barkersville?
a. 5miles
b. 10 miles
c. 150miles
d. 200 miles Answered by Harley Weston. 





The amount of material remaining on a reel 
20090304 

From James: Question from james:
I am after a standard calculation so that after each usage of the Reel I can get the Remaining Quantity in kilos left on the roll
below is an example of roll
THICKNESS: 30 MICRON
REEL WIDTH: 7.5 CM
REEL DIAMETER: 76 CM
REEL WEIGHT: 7.13 KILOS
The core centre has a 9cm diameter, the weight of the roll is excluding the core , and after each use the diameter of the role is measured.
I am a factory supervisor working on project and need this calculation info for template.. Thanks James Answered by Harley Weston. 





A shape with 10 sides 
20090303 

From Sandra: One of my son's math questions is as follows:
Suppose I have a shape with 10 sides. I choose a vertex then draw lines to the other vertices that dont share sides with the first vertex. How many vertices will that be and why? Answered by Penny Nom. 





The area of a 5sided lot 
20090302 

From Linda: I have a problem I'm hoping you can provide some help with. When I check the property information for our home on our District of North Vancouver website, it shows that our property is supposed to be 1146.99 Square Metres. Yet another property which has identical measurements is listed as having 1173.7 Square Metres. I would like to figure out who is correct. Answered by Harley Weston. 





An array with 2 more rows than columns 
20090228 

From Mario: Write a division sentence modeled by an array that has 2 more rows than the number in each row. Answered by Penny Nom. 





Simplify the square root of 125 x^2 
20090227 

From Ashley: √125x²
How do you simplify this equation assuming that variables can represent any real number? Answered by Robert Dawson. 





Triangles within triangles 
20090224 

From Mari: a large shaded triangle changes each day with a white triangle appearing
in the center of each shaded one. If this pattern continues, how many white
triangles will be there on the 6th day? On the 6th day, what fraction of
the large outer triangle will be white?THANKS! Answered by Robert Dawson. 





Augmented matrix: independent, dependent, or inconsistent? 
20090223 

From Anna: Perform row operations on the augmented matrix as far as necessary to determine whether the system is independent, dependent, or inconsistent.
x + y + z = 11
x  y + 3z = 5
2x + 2y + 2z = 15 Answered by Harley Weston. 





Pressure at Given Depth 
20090222 

From Tamara: A sea is 3km deep. The average density of sea water there is 1020 kg/m^3. What is the water pressure at the bottom? Answered by Janice Cotcher. 





Find the resultant of this displacement pair 
20090222 

From katydidit: Find the resultant of this displacement pair:
500 miles at 75 degrees east of north and
1500 miles at 20 degrees west of south.
How do I graph this and how do I solve this problem? Answered by Penny Nom. 





What deminsions should my box be? 
20090219 

From Mary: My item is 57cm x 36cm x 6cm and I want to put 20 items is 1 box. What deminsions should my box be? Answered by Stephen La Rocque. 





Angle of depression 
20090218 

From Meeka: An aircraft flying at an altitude of 2000m is approaching an airport.
If the angle of depression of the airport is 5 degrees, what is the distance from the plane to the airport measured along the ground?
Round your answer to the nearest tenth of a kilometer. Answered by Robert Dawson. 





Miles per hour to kilometers per second 
20090217 

From Tamara: If a car goes 60 miles in an hour how many kilometres will it go in a second? Answered by Penny Nom. 





Rent and a commission 
20090217 

From cliff: a landlord receives $95.00 rent 5% commission was paid to get to $95.00 what was the original number. The answer is obvious but what is the formula. Thanks. Cliff Answered by Penny Nom. 





The sides of a polygonal building 
20090213 

From mark: length of sides of an 18 ft.diameter bldg
i need to find out if i should build an octagon or decagon to keep the
sides of the bldg at 8ft or less. how do i figure the length of the sides
of each? Answered by Penny Nom. 





Can you convert numbers with units to percents? 
20090212 

From Kenneth: To change a number to a percent, move the decimal two places to the right and add a percent sign.
For example, 0.35875 = 35.875%.
If the number has a dollar sign or some other kind of unit, for example, pounds, feet, etc. how is the number converted to a percentage.
For example, change $0.35875 and 0.75 lbs. to a percentage. How is this done. I have never seen $35.875% or 75 lbs.% before. Answered by Robert Dawson and Harley Weston. 





Cubic feet gas to grams of gas 
20090211 

From tim: I was trying to convert cubic feet gas to grams of gas. Is there a formula to complete this task? Answered by Robert Dawson. 





Cubic centimeters and ounces 
20090206 

From Dawn: 1 syringe contains 5.5cc of medicine & cost $13.50
1 2 oz bottle of medicine cost $17.50
How many cc's in 2 oz, & which is the better deal? Answered by Stephen La Rocque. 





A 306090 triangle 
20090203 

From Inez: If you have a 306090 triangle and the only side you get is 73 and a 90 degree box, how do you find the area? Answered by Penny Nom. 





Calculating markup 
20090203 

From Tonya: I'm trying to figure out the formula for the following, I have a product that I want to receive a certain profit, but with this product I also have to pay a percentage of commission to someone. I need to know how to calculate my new selling price taking into account the markup percentage, but I don't want my cut to be lowered. I have calculated the markup percentage to get my new selling price with the commission, but it lowers my cut once I pay the commission and I don't want it to do that. Thanks Answered by Penny Nom. 





Simultaneous equations with an xy term 
20090201 

From angelee: xy+5x2y10=0
2x+y=1 Answered by Penny Nom. 





limit sinx/x 
20090130 

From Jackie: how to evaluate limit sinx/x as x tends to zero if x is in degrees Answered by Stephen La Rocque and Harley Weston. 





25,000 pounds of sheet metal 
20090127 

From JESSICA: I need to convert 25,000 lbs. of 32x48 sheet metal into total sq. feet. What would be my formula? Answered by Robert Dawson. 





The dimensions of a pool 
20090118 

From denise: a rectangular swimming pool is three times as long as it is wide. if the perimeter of the pool is 320 feet, what are its dimensions Answered by Penny Nom. 





The whole number that precedes a number w+3 
20090117 

From Morgan: write a variable expression for
"The whole number that precedes a number w+3" Answered by Penny Nom. 





Fuel in a tank 
20090116 

From Steve: I am not a math expert and want help seeing how much fuel is in a tank at one given time the tank that i have is 27 inches round. It is 69 inches long. laying length ways. it holds 140 gallons of fuel at fill up. I do know that it would hold less at the bottom of the tank an more in the center. Is there anybody that could just give me the figures by the inch without a formula. thanks for your time Answered by Stephen La Rocque. 





0.0708 lbs per linear yard 
20090116 

From Kevin: If I know that my product is .0708lbs per linear yard how do I calculate how many Linear yards are in a lb? Answered by Penny Nom. 





An expression for q quarters and n nickles 
20090116 

From Morgan: a variable expression for:
"The value in cents of q quarters and n nickels" Answered by Penny Nom. 





Does probability apply here? 
20090115 

From Paul: Suppose I have a dice in my hand that I am about to roll. The probability that I roll a six is, all things being equal, 1/6. I accept that.
Suppose now the I roll the dice and immediately cup my hand over the result. What is the probability that I have rolled a six? People seem to want to say it is still 1/6. But it can't be can it!? It is surely either 1 or 0, depending on whether I have in fact rolled a six? Answered by Robert Dawson. 





A one cubic mile lake 
20090109 

From dye: how many liters are in a one cubic mile lake Answered by Robert Dawson. 





660 yards = ?? miles 
20090108 

From Ashley: How do I convert yards to miles, specifically, 660 yards = x miles. Please show work so I can figure other problems out. Answered by Penny Nom. 





(a x b) intersect (b x a) 
20090108 

From sean: is it possible to have two sets such that
n((a X b) intersect (b X a) =3 Answered by Harley Weston. 





Numbers or Percentage or probability or what? 
20090107 

From Chew: Teacher A teaches 50 students and 45 of them obtained straight As.
Teacher B teaches 5 students and 5 of them obtained straight As.
Which teacher would you send you child to and why? Answered by Robert Dawson and Harley Weston. 





Converting grams to milliliters 
20090104 

From Faiza: I was looking for how to convert grams into mL and I read on this site
to convert one to the other you need to know what substance you are measuring.
so if I am measuring sugar or any of the baking ingredient like flour how do
I convert them from grams to mL is there a simple method I can use to do that? Answered by Penny Nom. 





The square root of 164 
20081231 

From Melissa: How do you simplify the square root of 164? Answered by Stephen La Rocque. 





The volume of a feed hopper 
20081218 

From John: I need to calculate the volume of a feed hopper, and I'm not sure how to break it down. The top of the hopper is 36" x 36", it is 30" deep, and ends at a 6" x 6" plate. One side of the hopper is straight top to bottom, of course tapering on two sides to meet at the plate. The other three sides angle down at about 75 degrees. I need to determine the cubic foot volume of this hopper (it is used for ground coffee) so I can configure a vibrator to knock down residual grounds. Thanks. Answered by Robert Dawson. 





The angle between two lines 
20081217 

From abhi: how to calculate the angle between two lines, given the length of the lines..
angle should vary from 0  360 in the counterclockwise direction Answered by Robert Dawson and Harley Weston. 





650g+2kg+195g=how many kg 
20081211 

From christian: 650g+2kg+195g=how many kg Answered by Penny. 





Wall covering 
20081210 

From Jeanie: I need to convert 14 LY of wallcovering (54" wide) to square feet. Can you please help me? Answered by Penny Nom. 





The volume of a pipe 
20081210 

From Walter: What is the volume of a pipe 7.92 inches inside diameter and 22 km. long in cubic feet of water Answered by Robert Dawson and Harley Weston. 





A wine decanter 
20081210 

From Suzanne: I am trying to buy a wine decanter for my dad for Christmas. One big
problem I am having shopping online is finding the right size. Wine is sold
by metric ml, with a standard bottle holding 750ml of wine. Decanters are
measured by oz, and the sizes are all over the place, with one site alone
having sizes 25oz, 26 1/2oz, 50oz, 59 1/8oz, and 68oz.
Can you help me with metric conversions so I can figure out how much wine
these decanters hold? Like everybody else, I need this as soon as possible
so I can get it shipped in time for Christmas. (I'm disabled & don't drive, so
online shopping is my only way to get gifts.)
Thanks for your help!
Suzanne Answered by Chris Fisher and Robert Dawson. 





What is one trillion divided by 10? 
20081209 

From mark: can you please tell me what one trillion divided by 10 is Answered by Robert Dawson and Penny Nom. 





The volume of a yogurt pot 
20081204 

From Robyn: Okay, I know you have some answers on converting this already, but I can not convert the yoghurt pot I need yet into ml.
Is there some way to explain this using the yoghurt as an example?
The pot's 150g of lowfat strawberry yoghurt... would the 'lowfat' have an effect on this?
I'm sorry if this is a bother for you to answer, I just don't seem to be able to get it...
Have a nice day.
 Robyn Answered by Janice Cotcher and Penny Nom. 





Division in different bases 
20081202 

From MICHELLE: DIVIDE 538 BY 14 IN BASE 2, 3, 4 & 5 Answered by Penny. 





3 equidistant points 
20081201 

From Damien: How do you find 3 equidistant points (C,D,E) on a line between point A(Xa, Ya) and point B(Xb, Yb) so that AC, CD, DE and EB are all equal? Answered by Chris Fisher. 





What is so important about quadratics? 
20081129 

From zoe: what is so important about quadratics? Answered by Harley Weston. 





Dividing Large Numbers 
20081126 

From Mark: what is 7.9 trillion divided by 301 million? Answered by Janice Cotcher. 





The path of a small sailboat 
20081119 

From jane: a sailor in a small sailboat encounters shifting winds. she sails 2.00 km East
then 3.40 km North East, then an additional distance in an unknown direction. Her final position
is 6.68 km directly east of the starting point. find the magnitude & direction
of the third leg of the voyage. Answered by Harley Weston. 





An algebraic exercise with fractions and radicals 
20081118 

From Rubιn: Question from Rubιn, a teacher:
I have the ecuation:
U = [yb / (ab+a^2)]^1/2 + [ya / (ab+b^2)]^1/2
I know for sure this reduces to
U = [y (1/a + 1/b)]^1/2
but I cannot find a way to get into that result!
Thanks Answered by Rubιn Osuna. 





The midpoint o a line segment 
20081115 

From Jane: The vertices of a triangle are at (1,7), (6,1) and (0,3). Find the coordinates of the midpoints of the sides. Answered by Penny Nom. 





A ratio to a decimal 
20081114 

From manny: Express 22 : 5 as a decimal. Round to the nearest hundredth Answered by Penny Nom. 





How far are the boats apart? 
20081114 

From dom: Two boats leave port at the same time. They leave at 150 degree angle. One boat travels at 10mph and the other at 20mph. After two hours how far are the boats apart? Answered by Penny Nom. 





The angles and sides of a triangle 
20081113 

From JAMIE: a triangle with a side(b)37m an angle(C)70degrees and (a)79m find values of angles A and B and length of side c Answered by Stephen La Rocque. 





An odd shaped lot 
20081113 

From Janice: Hi I am attaching a survey of an odd shaped real estate lot. I am hoping
you can help me determine the acreage.
Janice Answered by Harley Weston. 





How do you work out 2/17 as a decimal? 
20081113 

From p: how do you work out 2/17 as a decimal? Answered by Penny Nom. 





A barrel on its side 
20081113 

From Dave: Question from Dave:
How many gallons are left in a 36x60 in. barrel (laying on its side) and has 16 in. of gasoline left. I have attached a diagram. Answered by Harley Weston. 





Math and nursing 
20081110 

From alina: how many math do you net for nurse Answered by Stephen La Rocque. 





A flagpole and a yardstick 
20081107 

From Wanda: One boy holds a yardstick vertically at a point 40 feet from the base of the flagpole. The other boy backs away from the pole to a point where he sights the top of the pole over the top of the yardstick. If his position is 1 ft 9 in from the yardstick and his eye level is 2 ft above the ground, find the height of the flagpole. Answered by Penny Nom. 





A bay window 
20081030 

From Scott: Given the length of an arc, the rise of an arc, and the number of segments
that I need to divide the arc into  how do I determine the length of each
segment? Imagine a bay window. It could have 5 side or 7 sides, just as
an example. How do I determine the width of each window given that the
unit will be mounted into a frame with a 96 inch opening. The rise of the
unit will extend out 18 inches. Lets say that the number of single windows
unit within the unit is 5. How wide should each window be? Do you
understand? Answered by Harley Weston. 





The length of a rectangle is 6 inches less than 3 times its width. 
20081026 

From Angela: The length of a rectangle is 6 inches less than 3 times its width. Find the
dimensions of the rectangle if its area is 45 square inches. Answered by Penny Nom. 





Put in lowest terms 6a^2c/8ab 
20081024 

From hana: put in lowest terms 6a^2c/8ab Answered by Stephen La Rocque. 





A falling block 
20081018 

From KOBINA: A 50 kg block being held at rest 20m above the ground is released. the block falls (no friction). how fast is the block traveling (in m/sec) when it has lost 40% of its original potential energy. Answered by Stephen La Rocque. 





Two equations in two unknowns 
20081017 

From Dushayne: Please help me in solving this problem:
a. 3x4y=32
5x+2y=10
b. 2x+3y=11
4x+3y=10 Answered by Penny Nom. 





The dimensions of a rectangle 
20081016 

From cristine: the area of a rectangle is 675sq.cm.
if the width is 1/3 of the length.
find the dimensions of the rectangle.... Answered by Penny Nom. 





Millimeters to inches 
20081015 

From diane: can you convert milliliters to inches? Answered by Penny Nom. 





The sides of an octagon 
20081012 

From side lengthsGarry: I need the length of the sides and the degrees of the angles for a 30 inch diameter
octagon Answered by Janice Cotcher. 





The dimensions of a pool 
20081008 

From Justine: This may be a really silly question but I am trying to work out what the possible dimension a pool may be if we have 20m length of wall of an above ground pool (laid out flat on ground)
We have been given a second hand above ground pool and we know it was in an oval configuration and we are just trying to get a guesstimate of the potential size it may be as the people couldn't tell us the size Answered by Penny Nom. 





Algebraic fractions 
20081006 

From Kayla: (x^29)/x times (x^34x)/(x^2+5x+6) Answered by Harley Weston. 





A product of positive and negative numbers 
20081003 

From kaylou: Suppose you were given 13 numbers and asked to find their product.
Seven of the numbers were positive, and the rest were negative.
Would your product be positive or negative? Why? Answered by Penny Nom. 





The unusable space in a container 
20081002 

From Billy: an object is 42 inches long, 29 inches wide, and 69 inches high. The usable capacity of this container is 36.4 cubic feet. How much space in percentage is left over from the container? Answered by Penny Nom. 





Does an oval have sides? 
20081002 

From reid: My 6 yo neice came home with her math homework and she was supposed to identify which objects had sides.One of the objects was an oval.I don't believe it has sides because it is curved and I don't think that would make it an object with sides.What would be the correct answer?Thanks,Reid Answered by Janice Cotcher. 





The length of a tank 
20081001 

From alex: I have a tank which I can only partly see. It is 70cms wide, 45 cm deep and hold 500litres. How long is it? Answered by Harley Weston. 





Conversion to cubic feet 
20081001 

From Dorothy: What is the cubic feet of an item that is 7"x16 7/8"x19" Answered by Harley Weston. 





z(z+1)x(x+1) / zx 
20080930 

From sylvia: z(z+1)x(x+1) / zx
HOW DO I SIMPLIFY THIS Answered by Penny Nom. 





3,6,10,15,and 21 
20080928 

From jarred: i am currently stumped on a math project that requires me to find out the recursive formula for a sequence of numbers. the numbers in the sequence are 3,6,10,15,and 21. Thank you for your time. Answered by Walter Whiteley. 





144 square inches 
20080927 

From mike: how much cm is in 144 square inches? Answered by Penny Nom. 





Simplify 6(a+2b)+8a16b 
20080927 

From madison: 6(a+2b)+8a16b Answered by Penny Nom. 





Three equal ratios 
20080926 

From Jodi: For the ratio given, find three equal ratios: 2 miles/8 minutes Answered by Penny Nom. 





Sample variance: inches to centimeters 
20080922 

From Anita: The average height of a sample of basketball players is 6 feet, 2 inches or 74 inches.
The standard deviation of this sample of players is 4 inches. If each person's height were to be multiplied by 2.54, what would be the value of the resulting sample variance? Answered by Harley Weston. 





The sides of an octagon 
20080921 

From mark: I need to know the measurements of an octagon with a inside diameter of 34.5 inches from side to side Answered by Penny Nom. 





Simplify [[1/(x+3)]1/3]/x 
20080919 

From diana: How does [[1/(x+3)]1/3]/x simplify Answered by Harley Weston. 





Oils and fats 
20080918 

From Barry: I'm doing a nutrition assignment and I'm adding up my Oils and Fats category.
I have 10ml of butter to add to 31g of fat so I'm trying to figure out what to do or I should say how to figure out the answer.
Barry Answered by Penny Nom. 





The weight of a concrete cylinder 
20080918 

From Curtis: I am trying to calculate the weight of a concrete cylinder. The diameter is 56" and the thickness or depth is 24". Can anyone help me? If possible I would like to see the formula as to how the answer was derived. Thank you Answered by Harley Weston. 





Simplifying equations 
20080918 

From diana: I do not know how to simplify equations. How does 5x^27X+2 become (x1) (5x2)? Answered by Penny Nom. 





Cubic yards and quarts 
20080916 

From Mary: I need 2 yards of soil, how many quarts is this? Answered by Penny Nom. 





Three addends that sum to ten 
20080913 

From Alfred: How many probabilities are there to have 3 addends to get a sum of 10? What is the formula? Answered by Harley Weston. 





A number that divides by six but not by three 
20080912 

From Ken: A number that divides by six but not by three Answered by Stephen La Rocque and Victoria West. 





How would put .12 with 2 repeating into a fraction? 
20080909 

From Savanna: How would put .12 with 2 repeating in fraction?
Savanna! Answered by Penny Nom. 





How many ml are in 40 grams? 
20080909 

From Nancy: I need to know how many ml are in 40 grams. So what is the base 1ml= how may grams Answered by Harley Weston. 





An exclusion zone around a triangle 
20080907 

From Awrongo: A long time ago Mr Gibson found an island shaped as a triangle with three straight shores of length 3 km,4 km and 5 km. He declared an 'exclusion zone' around his island and forbade anyone to come within 1 km of his shore. What was the area of his exclusion zone? Answered by Stephen La Rocque and Penny Nom. 





A security camera 
20080907 

From Rita: A security camera in a neighborhhod carnival is mounted on a wall 9 feet above the floor inside a video gallery. What angle of depression should be used if the camera is to be directed to a spot 6 feet above the floor and 12 feet from the wall? Answered by Stephen La Rocque and Harley Weston. 





Simplify ((5/7)/(5/14)) + (3/4) 
20080906 

From Emal: How do you simplify completely: ((5/7)/(5/14)) + (3/4)? Answered by Penny Nom. 





3 miles in 6 seconds 
20080905 

From Grant: if a rocket sled is traveling 3 miles in 6 seconds, how fast is it going in miles per hour? Answered by Harley Weston. 





The selling price 
20080904 

From Robert: Client wants to sell his property providing he is left with 100000.00$ net.
How do I calculate selling price if commission is 6% and taxes on the commission 6% Fed and 7.5%prov.
I'm taking the real estate class and this one really got me. Answered by Penny Nom. 





I need an equation that best fits these numbers. 
20080903 

From Vallatini,: Attached, please find a plotted curve (pdf file). I have pulled values from this curve (see below). I need an equation that best fits these numbers. Can you help? Answered by Harley Weston. 





An algebraic expression 
20080829 

From Antonio: write a variable expression for 9 less than k Answered by Penny Nom. 





Long Division with Decimals 
20080828 

From Ghita: I need help with these 2 questions:
Find the quotients:
52.576 divided by 21
71.331 divided by 93
Ralph spent 5/9 of an hour mixing paints and 7/9 of an hour painting.How much time in all did Ralph spend on his project?
Thank you,Please answer soon Answered by Janice Cotcher. 





557 mL of benzaldehyde 
20080828 

From Kara: Calculate the mass of 557 mL of benzaldehyde. The density of benzaldehyde is 1.04 g/mL. Answered by Penny Nom. 





The square root of a fraction 
20080824 

From Lauren: How do you solve square roots of fractions? Does the format change if it is either a proper or an improper fraction?
Ex. the square root of 1/4 or the square roots of 80/25 Answered by Penny Nom. 





Radii and Chords Create a NonRight Triangle 
20080822 

From Beary: AOC is a diameter of circle O. Line AB is 12, and lines OA and OC (the radii) are 10. Find the length of line BO and chord BC. Answered by Janice Cotcher. 





Simplifying Algebraic Expressions 
20080822 

From Jacky: x^2y^2+4x+4y Answered by Penny Nom. 





Converting centimetres to metres 
20080821 

From walter: how do you convert the smaller unit to a decimal of the larger unit and then solve
17 m  130 cm Answered by Penny Nom. 





Angular & Linear Speed from a Sine Graph 
20080819 

From Kim: Kim, a student:
I am given a graph with a wave. The amplitude is 5cm and the period is 4cm. I am suppose to find the angular speed. What I need to know is the formula for angular speed and how do I use these numbers to get the correct answer. Answered by Janice Cotcher. 





Metres and miles 
20080818 

From Bill: I enter a race that is 10,000 meters long,how many miles do i have to run? Answered by Victoria West. 





Solving for Shared Height of Two Right Triangles 
20080817 

From Heidi: find the height of a triangle, which can be split into two right triangles, but the base (50m) is not split equally in half. one end of the base is 40 degrees, while the other is 30 degrees. Answered by Janice Cotcher. 





Similar Triangles Given a Median 
20080817 

From RAM: Sides AB , AC and median AD of a triangle ABC are respectively proportional to
PQ PR and median PM of another triangle PQR. Show that ABC is similar to PQR Answered by Janice Cotcher. 





Converting to cubic yards 
20080815 

From Lisa: I need to convert 32,000 square feet, 5 inches deep to cubic yards. Can you help me?
Thank you Answered by Harley Weston. 





Similar triangles 
20080812 

From ramarao: D is a point on side BC of a triangle ABC such that BD/CD=AB/AC. prove that AD is the bisector
AD is the bisector of BAC Answered by Chris Fisher. 





Arclength and sectorangle 
20080806 

From Benson: If chord length, radius are given, How to find the sector angle and arclength Answered by Janice Cotcher. 





24 in by 14 in by 14 in in cubic feet 
20080805 

From Tom: I have a box that has internal dimensions of: 24in. H x 14in. W x 14in. D.
How many cubic feet is this internal space? Answered by Penny Nom and Victoria West. 





Why can't you divide by zero? 
20080804 

From Donna: Why can't you divide by zero? Answered by Chris Fisher. 





Lot size of a four sided lot 
20080730 

From JAMES: I'm trying to find out this lot
size in acres.
I looked at a bunch of your suggestions, but I guess
I'm not smart enough
to figure it out.. I have attached an image of the
lot, hopefully with
enough info. for you..
Thanks,
Jim Answered by Penny Nom. 





Right Sided Limit of an Exponential Function 
20080729 

From joseph: I am trying to find the limit as X approaches 0 from the positive side of x to the sin of x
which look like this lim x^sinx
x>0+ Answered by Harley Weston. 





Trigonometric 
20080728 

From kiran: In triangle , Sin@ = ? Answered by Penny Nom. 





What is the domain of (f/g)x? 
20080728 

From Warren: If f(x)=3x5 and g(x) = square root of x5, what is the domain of (f/g)x? Answered by Penny Nom. 





Alpha level 
20080723 

From anonymous: What is the advantage of using an alpha level of .01 versus a level of .05, What is the disadvantage of using a smaller alpha level? Answered by Janice Cotcher. 





Simultaneous equations 
20080723 

From Franco: Solve
3 D + E  F = 10
2 D  F = 4
3 D  4 E  F = 25
Franco Answered by Penny Nom. 





Choosing 4 numbers from 70 numbers 
20080721 

From Jeannine: When using numbers from 1 to 70 in sets of 4, how many combinations are there without having the same combination twice?
Thanks Answered by Penny Nom. 





Three consecutive positive integers 
20080720 

From AC: find three consecutive positive integers such that the product of the first and third, minus the second, is 1 more than 4 times the third Answered by Penny Nom. 





A bijection from (0,1)x(0,1) to (0,1) 
20080720 

From Adam: I'm trying to prove that the function that takes the open square (0,1)x(0,1) to (0,1) is a bijection (and hence a continuum).
If we take an element (x,y) of (0,1)x(0,1) and represent (x,y) as (0.x1 x2 x3 x4..., 0.y1 y2 y3 y4...) aka x1 represents the tenths digit of x, x2 represents the hundredths, etc. Then we can define a function
f((x,y)) = 0.x1 y1 x2 y2 x3 y3... However, this is not a bijection. I hypothesize this is because you'd be unable to create the number 0.1 as x=0.1 and would have to be y=0, which contradicts the open interval (0,1) defined for y. We have been told though, if we create the same function, except that we "group" 9's with their next digit into a "block"
we can create a bijection. For example, if x=0.786923 and y=0.699213, then we define x1 to x3 as normal, but x4= 92, and x5=3. For y, we define y1 as normal, but y2=992, and y3 to y4 as normal. hence f((x,y)) = 0.7 6 8 992 6 1 92 3 3.
My questions are a) is my hypothesis on why the original function is not a bijection correct? b) why does the special blocking in the new function make a bijection? Answered by Victoria West. 





A silo with a flat side 
20080714 

From Amy: Without using the Pythagorean Theorem, determine the capacity of a silo in cubic feet of grain if: the cylindershaped silo has one flat, rectangular face that rests against the side of the barn; the height of the silo is 30 feet and the face resting against the barn is 10 feet wide; the barn is approximately 5 feet from the center of the silo. Answered by Harley Weston. 





A four sided lot 
20080709 

From michelle: the front is 65.29
left side 162.26
the back 155.00
right side 101.01
right angle=50.00
left angle= 153.30 Answered by Harley Weston. 





Neither prime nor composite 
20080708 

From saloni: Give the counting number which is neither prime nor composite ? Answered by Penny Nom. 





Divisibility by 11 
20080704 

From Peter: For what single digit value of n is the number n53nn672 divisible by 11? Answered by Leeanne Boehm. 





Composition of two functions 
20080704 

From Kristian: f(x)= the square of x add to 1 and g(x)=1/x
find: (f o g)x Answered by Penny Nom. 





Polynomial division and remainders 
20080702 

From RAM: If the polynomial x46x3+16x225x+10 is divided by another polynomial x22x+k, the remainder
comes out to be x+a. Find k and a. Answered by Janet Cotcher and Harley Weston. 





Kilometers per liters to miles per gallon 
20080626 

From margaret: we travelled 130 kilometers on 10 liters of gas. How many miles to the gallon did I get Answered by Penny Nom. 





The smallest number divisible by 1 to 9 
20080626 

From Peggy: What is the smallest number divisible by each of the first nine counting numbers? Answered by Penny Nom. 





A six sided lot 
20080625 

From Zack: Please help me find the area of my lot. I am sending a fax of the drawing and dimensions.
Zack Answered by Harley Weston. 





How many pounds in 300 grams? 
20080624 

From Renelda: How many pounds in 300 grams? Can you send the formula? Thanks Answered by Penny Nom. 





The sum of the digits of a number 
20080623 

From Ben: Question: Using mathematical induction, prove that if the sum of the digits of a number is divisible by three, then the number itself is also divisible by 3. Answered by Penny Nom. 





9(d+5)=3(d3)+6d 
20080619 

From davontay: 9(d+5)=3(d3)+6d Answered by Harley Weston. 





Concrete blocks 
20080618 

From marvin: How many cement blocks do i need to build a 8 ft. tall wall x 1,300 ft. long? Answered by Harley Weston. 





How do you change bases? 
20080617 

From Peter: How do you change bases eg. 121 from base 3 to base 5? Answered by Penny Nom. 





2(x  1)^2 + 8 
20080612 

From kasondra: y=2(x1)2[thats a square] +8 that need to be put in standard form
the answer is y= 2x2 4x + 6
i got y= 2x2 4x 4
i just don't get how my teacher got that answer Answered by Penny Nom. 





The weight of concrete 
20080611 

From Daniel: I need to calculate the weight of Concrete in a slab that measures 2' x 4' x 4" thick.
I am pricing out a job and have two different size stones to work with, the second stone measures
2' x 2' x 4". Answered by Harley Weston. 





What are the dimensions of the rectangle? 
20080611 

From Denise: A rectangle has a diagonal that is 3.6 feet longer than the length and 7.1 feet longer than the width. What are the dimensions of the rectangle? Answered by Claude Tardif and Victoria West. 





A recursive formula for 9, 18, 36, 27, ... 
20080605 

From Rita: I am having trouble understanding how to write formulas (I should say create formulas) from a given sequence.
It does not matter what sort of sequence it is. The confusion remains.
I have not found a textbook or easy math book that explains this process for the average Joe to grasp.
Here are the two questions:
(1) Write a recursive formula for the sequence
9, 18, 36, 72, ...
(2) Write a recursive formula for the sequence
3, 3(sqrt{3}), 9, 9(sqrt{3}) Answered by Penny Nom. 





A 4 sided lot 
20080603 

From Pat: If a lot of property is: front 127.87, back 156.17, one side
is
129.73, the other side is 125.00, then how much total acreage is
this. Answered by Harley Weston. 





The area of a regular pentagon 
20080602 

From Jenna: I would like to know if there is a formula to find the area of a regular Pentagon that is not inscribed in a circle only apothem and side length are given. Answered by Penny Nom. 





4x^3  6x + 2 = 0 
20080528 

From paul: 4x^3  6x + 2 = 0 Answered by Janice Cotcher. 





Convert cubic inches to gallons 
20080526 

From Rosemarie: How do you convert cubic inches to gallons? Thanks for your help. Answered by Penny Nom. 





.5 cu ft of sand to lbs. 
20080525 

From rogersimmons: needtocovert .5 cu ft. of sand into lbs. Answered by Penny Nom. 





3 radical 48 +11 radical 75 
20080524 

From Maria: Add 3 radical 48 +11 radical 75. Write answer in simpliest form. Answered by Penny Nom. 





Double the the dimensions of a rectangle 
20080522 

From Destiny: Double the the dimensions of a rectangle that is 3 by 4 in. What is the area? Answered by Penny Nom. 





Volume/weight of a salt shedweight 
20080521 

From James: How do I find the volume/weight of a salt shed. I have a 3000 ton barn, I need a better way of finding how much salt to order as it gets used. I know how to calculate volume, how do i get tonnage from there?? Answered by Harley Weston. 





Nine digit numbers 
20080521 

From Alex: List of Nine digit numbers, that can be divided by nine? Answered by Janice Cotcher. 





1+1/1+1/x 
20080521 

From nadean: 1+1/1+1/x Answered by Penny Nom. 





A weird shaped lot 
20080521 

From James: Need to find square foot of a residential lot on a culdesac. Weird triangular shape. Measurements : 126.18 170.08 138.2 48.4 Answered by Harley Weston. 





Converting a decimal to a fraction 
20080519 

From judy: please explain how to get from the decimal number .3437 to the fraction 11/32 Answered by Leeanne Boehm. 





Guy wires for a tower 
20080519 

From larissa: a radio tower 500 feet high is located on the side of a hill ( the hill has an inclination to the horizontal of 5 degrees.) How long should two guy wires be if they are connected to the top of the tower and are secured at two points 100 feet directly above ( up the hill ) and directly below the base of the tower? Answered by Penny Nom. 





Fencing around a playground 
20080515 

From Vanessa: If the playground is a rectangle with it's width 10ft shorter than it's length,
and it can be enclosed by exactly 140ft of fence,
what is the length and width of the playground? Answered by Penny Nom. 





The fourth side of a property 
20080514 

From Penny: Property has 3 measurements and 2 angles and I want the altitude at a particular point. Corners are sw, nw, ne and se. 1 want the 4th saide measurement confirmed (we think 146.07') and the altitude measurement at 25' from sw (on the swse side)
The angles provided are interior at nw 67.38 degrees and the opposing corner se interior appears to be 68.58 degrees. the 3 sides with measurements are: sw to nw=54.07'. sw to se 146.07' and se to ne 53.57'. If you would help, we would really appreciate it. Thanks! Penny Answered by Harley Weston. 





How much seed do I need per plot? 
20080513 

From Jaye: The plot size is 5 m X 2 m. The seeding rate is 12Kg/ha. How much seed do I need per plot? I have failed to get a proper answer.
Thank you. Answered by Penny Nom. 





The weight of a concrete column 
20080511 

From russell: a cylindrical form is filled with a slow curing concrete. The base of the form
is 10 ft in radius, and height is 25 ft. while the concrete hardens, gravity
causes the density to vary from a density of 90 lbs/ft^3 at the bottom to a
density of 50 lb/ft^3 at the top. Assume that the density varies linearly
from the top to the bottom, and compute the total weight of the resulting
concrete column Answered by Harley Weston. 





Selling price 
20080510 

From Roxane: I'm trying to figure out the formula for the following, I have a product that
I want to receive a certain profit margin, but with this product I also have
to pay a percentage of commission to someone. I need to know how to
calculate my new selling price taking into account the markup percentage, but
I don't want my gross margin to be lowered. I have calculated the markup
percentage to get my new selling price with the commission, but it lowers
my profit margin once I pay the commission and I don't want it to do that. Answered by Penny Nom. 





The sides of an octagon 
20080507 

From Frank: Question from Frank, a parent:
Hi,
Need to lay out a 10 ft. diameter octagon on the ground. What is the
length of the
sides ? And the angles ? Answered by Harley Weston. 





Four cookies 
20080503 

From tashera: if a serving is 5 cookies. how many servings can i make from 4 cookies? Answered by Stephen La Rocque. 





How many gallons are in 1,500 liters? 
20080501 

From bambi: [How many gallons are in 1,500 liters? Answered by Penny Nom. 





Division by zero 
20080501 

From Bill: Why does multiplication have a favored status so as to make division by zero undefined? Answered by Harley Weston. 





1/35/6=1/x, solve for x 
20080501 

From Lavada: 1/35/6=1/x How do I solve this problem. Answered by Penny Nom. 





(9x^24)/(3x^25x+2) * (9x^4  6x^3 +4x^2)/(27x^4+8x) 
20080429 

From Jonathon: I don't remember how to solve an equation in the form of the following:
(9x^24)/(3x^25x+2) * (9x^4  6x^3 +4x^2)/(27x^4+8x) = Answered by Stephen La Rocque. 





Converting metric density 
20080428 

From Hilary: 10g/100ml=?g/?l
52g/100ml=?g/?l
65g/100ml=?g/?l
100g/100ml=?g/?l
137g/100ml=?g/?l
0.15g/100ml=?g/?l Answered by Penny Nom. 





WHY 144 where does this figure come from 
20080419 

From Sean: Why do you use the number 144 to divide
EG. length of timber 2 inches x 8 inches x 14 foot = 1.5 cubic feet
Calculation is 2x8x14 =224 divide by 144 = 1.5 WHY 144 where does this figure come from Answered by Leeanne Boehm. 





Simplify 5x^5/8 / 15x^2/12 
20080418 

From Kyler: 5x^5/8 / 15x^2/12 Divide the rational expressions. Simplify the results. Answered by Penny Nom. 





The three sides of a triangle 
20080416 

From Bridgett: The sum of the lengths of any 2 sides of a triangle must be greater than the third side. If the triangle has one side that is 11 CM, and the second side of the triangle is 4 cm less than twice the third side, what lengths do the 2nd and 3rd side have to be?
between 00000000 and 99999999 Answered by Stephen La Rocque. 





What is 300% as a fraction? 
20080414 

From Carli: what is 300% as a fraction Answered by Stephen La Rocque. 





A 13 cubic foot cylinder filled with sand 
20080412 

From Thomas: I have a 100 pound bag of sand. I need to know how much sand I will need to fill a 13 cubic foot cylinder Answered by Harley Weston. 





The capacity of a silo 
20080412 

From Candonn: I have a cement silo that is 30 ft. high and has a diameter of 12 ft.
I was wondering what the capacity of the silo is in tons of dry material.
The silo is flat on the bottom also. Answered by Penny Nom. 





Some 4 sided polygons 
20080411 

From kathy: I am a 4th grade student and need to complete this question:
I need to draw 2 polygons with 4 sides and 2 right angles. Please help. Thanks Answered by Penny Nom. 





Side lengths and angles in a regular octagon 
20080409 

From Lori: I am a builder and need to find the length of the sides of an octagon. I know the length between
the parallel sides (26 feet). What is the length of each side? What is the angle measurement? Answered by Harley Weston. 





The weight of 1 litre of milk 
20080407 

From IMRAN: WHAT WEIGHT IN KILOGRAMS DOES 1 LITRE OF MILK HAVE? Answered by Penny Nom. 





Composition of functions: feet, inches and yards 
20080405 

From Coya: write a function f(x) that converts feet to inches.Now write a function g(x) that converts yards to feet. Explain what the composite function f(g(x)) means. Then evaluate f(g(x)) for x = 3,6, and 9. Answered by Stephen La Rocque. 





Compatible numbers 
20080404 

From dawn: Need help. Estimate the quotient. Tell what compatible numbers you used.
817divided by 4 = Answered by Penny Nom. 





100 yards of cloth 
20080404 

From Leroy: (100 yards of cloth 48 inches = how many square yards) Answered by Penny Nom. 





Ounces and grams 
20080402 

From Rakesh: 7.2 oz per sq. yard equals ? __ grams per sq. meter
How I can measure the weight of a Jeans fabric (in oz)? And what is the rellation between grams and oz? Answered by Penny Nom. 





Common fraction to decimal fraction 
20080401 

From chadwick: how do I turn 3/32 into a decimal Answered by Penny Nom. 





2 ^ 2 + (6  9) / (3) + 4 * (2) 
20080401 

From Jeth: How do I simplify: 2 ^ 2 + (6  9) / (3) + 4 * (2) Answered by Penny Nom. 





Square feet and square yards 
20080401 

From Victor: 6200 sq. ft.into yards Answered by Penny Nom. 





A car tire full of concrete 
20080327 

From robert: I want to build a volleyball net support. I am using a car tire 24"odx16"id filled with concrete. how much will this weigh? thanks Answered by Penny Nom. 





Similar triangles 
20080326 

From Nisha: In triangle ABC, LM is parallel to AB. If AL=x3,AC=2x,BM=x2,BC=2x=3. Find x Answered by Penny Nom. 





Light years to miles 
20080324 

From Robert: HOW MANY MILES ARE THERE IN 7.5 BILLION LIGHT YEARS. Answered by Penny Nom. 





Converting ounces to milliliters 
20080321 

From kelly: As I have to drink 12  8 ounce glasses of water a day and my water bottle holds 591 ml, how many bottles of water must I drink? Answered by Penny Nom. 





How would I graph: x  2 divided by x^2  4? 
20080319 

From Sean: How would I graph: x  2 divided by x^2  4 using a method in extreme values of
functions or completing the square
x  2/ x^24 Answered by Stephen La Rocque. 





Determine the capacity of Farmer John's silo 
20080316 

From paula: Farmer John stores grain in a large silo located at the edge of his farm. The cylindershaped silo has one flat, rectangular face that rests against the side of his barn. The height of the silo is 30 feet and the face resting against the barn is 10 feet wide. If the barn is approximately 5 feet from the center of the silo, determine the capacity of Farmer Johns silo in cubic feet of grain. Answered by Penny Nom. 





The limit of (sin4x)/(tan9x) as x approaches zero 
20080314 

From stev: as x>0. How do you find the limit of f(x)=(sin4x)/(tan9X) Answered by Harley Weston. 





The length of a side of a square 
20080312 

From laura: if i had a square of 2.3 square meters what would its radius be?(in centimeters please) Answered by Penny Nom. 





Moving grain across the river 
20080312 

From Janice: Wesley needs to move 820 kg of grain across the river in a canoe that can carry no more than 120 kg. Wesley has a mass of 70 kg. What is the fewest number of trips he will have to make? A. 17 trips; B. 18 trips; C. 32 trips; D. 33 trips. Answered by Penny Nom. 





A ton of carbon dioxide 
20080311 

From claire: I want to know the size of a box if it contained a ton of Co2? Answered by Stephen La Rocque. 





Repeating decimals 
20080310 

From Blaine: Is it possible to put a repeating decimal number into a calculator to solve a problem?
EX: Write 39.3939... as a fraction. Answered by Penny Nom. 





Side lengths and area of a triangle 
20080308 

From angela: In the diagram of ABC the angle A is 65 the angle B is 70 and the side opposite vertex B is 7. Find the length of the side opposite vertex A and find the area of ABC Answered by Penny Nom. 





Composition of functions 
20080307 

From sharon: Find FoG(x)
F(x)= the square root of x9
G(x)= x^2
and also find GoF and their domains Answered by Penny Nom. 





Cubic feet to liters 
20080306 

From chase: if 1cu.ft=6.229 imp. gal and1 imp.gal=4.546 liters how many liters does of 128cuft. hold Answered by Penny Nom. 





The dimensions of a rectangle 
20080306 

From Julie: Find the dimensions of a rectangle with an area of 400. Width x ft.
Length (2x7)ft. Answered by Stephen La Rocque and Penny Nom. 





An arithmetic expression 
20080305 

From Kasani: evaluate the expression: 2^1[14  4(6)]  (7  3) Answered by Penny Nom. 





How large is a container that will hold 3.5 cu meters? 
20080305 

From Robert: If a company allows you to ship personal belongings while on an over seas assignment and the figure is 3.5 cubic meters. Just how much is the total area in square feet?? 10X10X10 or??? I just wanted to understand the size of a container that would hold 3.5 cubic meters!! Answered by Harley Weston. 





What was the ostrich's speed in miles per hour? 
20080303 

From jacob: If it took an ostrich 2.5 seconds to travel 110 feet and the average speed is 44 feet/ seconds, what was the ostrich's speed in miles per hour? Answered by Penny Nom. 





Convert from base 6 to base 12 
20080302 

From Jade: I am trying to convert 13405 base 6 to a base 12 number. I am not allowed to go into a base 10 number. How will can I base 12 without doing anything with base 10? Thank you kindly. Answered by Stephen La Rocque and Penny Nom. 





Simultaneous equations 
20080229 

From CONOR: I was wondering if you could help me with this problem
7x  5y = 1
3y = 4x Answered by Penny Nom. 





150 decimeters is how many centimeters 
20080229 

From gayle: 150 decimeters is how many centimeters Answered by Penny Nom. 





A new carpet 
20080228 

From Rhiannon: The Gatlins are buying a new carpet for their house. They need about
1,175 square feet of carpet. The carpet they buy is sold by the square yard.
Estimate the number of square yards of carpet they need. Do I use the
formula to find the volume or are? Answered by Penny Nom. 





Actural cost, selling price and commission 
20080221 

From LiSa: I have a question about a few things if anyone can answer...
ex.
actual cost (AC) = $1000
selling price (SP) = $
amount earned for company (C) = 15% of... selling price?
commission 1 (C1) = 2.5%
commission 2 (C2) = 2.5%
How would you calculate how much the company's commission amount would be as well as the amounts for the other 2 that get 2.5%? And what would the selling price be? (the 15% $ + 2.5% $ + 2.5% $ ?)
Is the 2.5% taken from the original amount? I am soooo confused!
If anyone could help, that would be great! Answered by Harley Weston. 





Algebraic fractions 
20080221 

From sergio: how to simplify
(x^2 +5x+6)/(x^2  4) x (x^2 5x+6)/(x^29) Answered by Stephen La Rocque. 





8% simple interest for 6 years 
20080220 

From Tiffany: cindy puts 5,025 in a bank account that earns a simple interest rate of 8%. How much money will be in the account at the end of 6 years? Answered by Stephen La Rocque and Penny Nom. 





The length of the third side of a triangle 
20080216 

From mary: I have an angle of 72 degrees and each of the sides are 5' long. What is the distance from each of the ends of the 5 feet to form a triangle. Answered by Stephen La Rocque. 





I am a 4digit number 
20080212 

From Nickie: I am a 4digit number with no repeating digits. I am divisible by 5, my first two digits (left to right) make a number divisible by 3, and my first three digits make a number divisible by 4. Also, my digits have a sum of 19 and I have the digit 7 in the thousands place. Who am I? Answered by Penny Nom. 





Drawing blocks from a box 
20080211 

From Inez: A box contains 3 red blocks and 1 green block. A block is chosen without looking and not put back. Then another block is chosen. What are the possible outcomes? Answered by Penny Nom. 





A flagpole and a statue 
20080209 

From Krista: A flagpole casts a ten meter (m) shadow at the same time as a six metre (m) statute beside it casts a two metre shadow. What is the height of the flagpole?? Answered by Steve La Rocque and Penny Nom. 





A three sided shape 
20080209 

From Tim: Question from Tim:
How would I calculate the area in square feet of a "triangle" with sides:
Base is 36 feet; height is 70 feet; and the thirs side is an arch (curve) of 77 feet. Answered by Harley Weston. 





Why is the number 1 neither prime nor composite? 
20080207 

From ronni: why is the number 1 neither prime nor composite? Answered by Harley Weston. 





Cost per square yard 
20080205 

From Terry: MY cost for seed is $325.00 per acre...i want to bring that down to $ per sqyard. Whats the formula? Answered by Penny Nom. 





The size of a lot 
20080202 

From linda: Hi, could you please tell me how close to an acre of land my lot is. The lot size is 140 ft by 200ft. I am trying to see how close to an acre it is. Answered by Penny Nom. 





The dimensions of a rectangle 
20080201 

From Evan: you are given that the area of a rectangle is 21.6in sq. find the base and the height of the rectangle. Answered by Penny Nom. 





The sign of the quotient of two integers 
20080201 

From michelle: without actually dividing, how can you decide whether the quotient of two integers is A. positive B. negative C. 0? Answered by Penny Nom. 





Bubbles trapped in the volumetric pipet 
20080131 

From Nursing: In determining the density of a liquid, a student left air bubbles trapped in the volumetric pipet. Did this give a density less than expected or greater than expected? Why? Answered by Penny Nom. 





The volume of a tank 
20080127 

From Fred: A cubic tank holds 1,000 kilograms of water what are the dimensions of the tank in meters? Answered by Harley Weston. 





Linear feet to metres 
20080125 

From Jillian: i have a measurement of something in linear feet. i dont know what a linear foot is so i want to convert it to meters to have an idea.
how do i convert. Answered by Penny Nom. 





Converting cubic inches to ounces 
20080122 

From kim: I am trying to find the formula to figure capacity in ounces for the following:
a rectangle 18" long, .75" wide, .75" deep ....
This is for an art project and the cost estimate. Thanks, Kim Answered by Penny Nom. 





How many combinations of 8614 are divisible by 7? 
20080122 

From Rebecca: How many combinations of 8614 are divisible by 7 equally (with no remainder)? Answered by Penny Nom. 





The cosine of an angle 
20080121 

From Kristine: Find measure of unknown side
cosA=0.5 Answered by Harley Weston. 





The angles of a triangle given the three sides 
20080117 

From Lucy: Is there a way to find the angles of a triangle just by knowing the lengths of it's sides?
It seems like the would be a relationship between the two, but I'm not sure. Answered by Stephen La Rocque and Harley Weston. 





Converting mg's to cc's 
20080117 

From sandy: i need to find out how to convert mg's to cc's i need to give 10 mg of liquid and 5 mg of liquid and i only have a dropper that measures cc's please help Answered by Stephen La Rocque and Harley Weston. 





Fact families with multiplication and division 
20080116 

From Donna: I am trying to help my granddaughter with some math homework. I
looked at what you have on fact families. Am I correct to assume that
the same process applies to multiplication and division as well? Her question
asks for fact families for 2, 8, & 16. Answered by Penny Nom. 





Explaining the factoring for the difference of cubes 
20080116 

From Bill: A student asked me where did the "difference of cubes" and "sum of cubes" come from. I did not have an answer for her. She is very bright and understands how they work but wanted to know where they derived from. Any help you can offer would be great. Thanks Answered by Stephen La Rocque. 





A 16 sided lot 
20080116 

From R: I am having a land of 16 irregular sides i know all the length of the sides how to calculate the
area of the land Answered by Harley Weston. 





Balancing on a fulcrum (net torque and equilbrium) 
20080115 

From Eric: If I have a 4" bar that has no weight value with a 275lb. weight on one side
and a 125lb. weight on the other side what would be the folcrum point? Please
keep the answer very simple. Also is there a fixed equation to figure folcrum points?
Is there an equation for if the 4" bar had a weight value? Answered by Stephen La Rocque. 





Two solutions using the law of sines 
20080114 

From Kate: I am working on the Law of Sines and I have a problem that says: Find a value for b so that the triangle has 2 solutions.
I am given that A = 36 degrees and a = 5. Now, I learned that for a triangle to have 2 solutions, h < a < b.
BUT...my answer key says the answer is: 5 < b < 5/sin 36. I can't figure out how to make this fit with h < a < b. Answered by Harley Weston. 





(303,000,000,000,303x3,300,000,033)/1,000,100,010,001 
20080113 

From Adrian: Give the result of the following computation as an integer.
(303,000,000,000,303x3,300,000,033)/1,000,100,010,001
N.B. No calculators allowed Answered by Penny Nom. 





Forces on an inclined plane 
20080110 

From Ron: A body that weighs 540lbs is caused to slide up an inclined plane with a uniform velocity by a force that acts parallel to the plane. For each foot of horizontal distance, there is a vertical rise of 2in. If the coefficient of sliding friction is 0.16, what force is required to move the body? Answered by Stephen La Rocque. 





Base salary plus commission 
20080110 

From mike: i need some help with this word problem.
in november 2001, hall kinion advertised an account executive position in savannah
georgia for a salesperson with experience selling internet services. the job
advertised a 3500 dollar base salary and 24000 dollar to 48000 dollar in
commissions in the first year. Assuming a 20 percent commission rate, how many
dollars in sales would u have to generate to earn 64000 dollars annually. Answered by Penny Nom. 





Sqrt(x^2 + y^2) 
20080110 

From Darcie: Can you simplify this problem?: square root of (x squared plus y squared).
Note: x squared plus y squared is under the radical. Answered by Penny Nom. 





Conversion 
20080108 

From Dom: Hi ,
Is it possible to convert 175 grams per metered squared to cm ?
tks
Dom Answered by Stephen La Rocque. 





How far is the jet from the lighthouse? 
20080107 

From Natalie: Question: A ship spots a lighthouse that is 53m high, at an angle of elevation of 7 degrees that is directly north of the ship. The same ship spots a jet travelling N62E at an altitude of 1500m with an angle of elevation of 15 degrees. How far is the jet from the lighthouse?
Natalie Answered by Harley Weston. 





Sigma notation 
20080106 

From jamelia: what is this word problem in sigma style i am so lost at this point my first time ever attempting this subject
1+2+3+4+5 Answered by Penny Nom. 





Lining up coins visually using geometry and trigonometry 
20071231 

From Jessica: a) In what order would you arrange a penny, a nickel, a dime, a quarter, and a halfdollar so that they all have the same apparent size? The diameters of the coins, in thousandths of inches, are as follows: penny, 750; nickel, 835; dime, 705; quarter, 955; halfdollar, 1205.
b) How should the coins be placed, if the distance between the dime and the halfdollar is 100 units?
How far from thw dime should your eye be to see that all the coins have the same apparent size?
c) What angle do the coins subtend when they have the same apparent size? Answered by Stephen La Rocque. 





Smallest cone containing a 4cm radius inscribed sphere 
20071219 

From Eva: A sphere with a radius of 4cm is inscribed into a cone. Find the minimum volume of the cone. Answered by Stephen La Rocque. 





Simplifying square roots 
20071219 

From Ciara: How would you calculate 2 to the square root of 8 plus 4 to the square root of 2 minus 5 to the square root of 2? Answered by Stephen La Rocque. 





What size room would I need for 220 cubic feet? 
20071218 

From Andy: What size room would I need for 220 cubic feet? What is the calculation I would use to find the answer to this problem? Answered by Penny Nom. 





System of equations 
20071206 

From Jenn: change the equation,xy=4 to form y=mx+b
the solution to the system of equations y=2x and y=x+3 is Answered by Stephen La Rocque. 





Chicken and goat feet 
20071205 

From Kim: Old McDonald raises goats and chickens. The animals have a total of
100 heads adn 360 feet. How many goats and how many chickens does Mr.
McDonald have? Answered by Stephen La Rocque and Penny Nom. 





Third side of a triangle 
20071205 

From Sudhir: How can we find the all positive integral values for the third side of a triangle, whose other two sides measure 15 and 20 respectively. (No other information viz. the type of triangle, area, perimeter or angles etc. is given.) Answered by Stephen La Rocque. 





A decision based on data 
20071204 

From manny: You have administered a standardized test of manual dexterity to two groups of 10 semi skilled workers. One of these two groups of workers will be employed by you to work in a warehouse with many fragile items. The higher the manual dexterity of a worker the less likelihood that worker will break significant inventory. Because of a unique contract you must hire all 10 employees from one of the two groups and none of the employees from the other.
You must decide which group to choose. Choose at least two measures of central tendency and at least one measure of dispersion for each group and use those to make your choice. Be sure to justify your choice with at least one page of discussion and analysis. Answered by Penny Nom. 





Ramp height 
20071203 

From Steve: I need to find the height of a angle.
23 degree angle at 12 feet of length is how high from the ground? Answered by Stephen La Rocque. 





Converting grams of hair spray into milliliters 
20071202 

From komal: I am confused that i am converting 75grams of hair spray ( liquid) into ML? but i couldnt get the answer what is perfect answer for that please help me for this thing. Answered by Penny Nom. 





The dimensions of a box 
20071130 

From nephi: if i wanted to make a box that was 0.35 ~ 0.7 Cubic Feet on the inside how would i go about making the measurements for the outside? Answered by Penny Nom. 





Transformations and compositions 
20071129 

From mary: Is there any possible relationship between composite functions and the concept of function transformations? Answered by Harley Weston. 





Density 
20071129 

From jessuca: what is the density for 40g / 2 mL Answered by Penny Nom. 





The width of a property 
20071129 

From Angie: I need to know what the footage is to find 8.1 acres knowing that the North boundary is 1309' Answered by Penny Nom. 





The perimeter of Wisconsin 
20071126 

From Kyle: I am doing a project and I need to figure out the total perimeter of wisconsin in miles
and only know the square miles of Wisconsin which is 65,503 and I need to get that to miles
I have no clue how to do this. I've looked all of the computer for answers but got none.
Thanks Answered by Leeanne Boehm and Penny Nom. 





A curve sketch 
20071122 

From Ahson: Find critical points, determine the monotonicity and concavity and sketch
a graph of f(x) with any local maximum, local minimum and inflection
points labeled:
1. f(x) = x^4  x^3  3x^2 + 1 Answered by Harley Weston. 





The definition of the sine function 
20071122 

From Indrajit: I need a explanation in this theory.......if sinθ = p/h...then
sin 90 deg. = p/h
or 1 = p/h
or p=h .....how can a perpendicular be equal to a hypotenuse.??? Answered by Harley Weston. 





Area of a 17sided lot 
20071121 

From Lynda: My uncle is wanting to buy this piece of land [a 17sided polygon] but we are questioning the acerage total. the measurements are [on the attached diagram]. Answered by Stephen La Rocque. 





I know it's heavy, but how heavy, per linear foot? 
20071119 

From Gary: I am trying to find out the weight of a linear foot of a steel bar with the following measurements.
Thickness  1.125"
Length  120"
Height  18"
Density of carbon steel  .2837
I know it's heavy, but how heavy, per linear foot? Answered by Stephen La Rocque. 





Cubic feet and gallons 
20071119 

From Leonard: Every conversion I find to convert a cubic foot to a gallon is in liquid.
Question, how would 1 cubic foot convert to gallons in dry measurement?
Example say you have 1 Gallon of packing peanuts how many cubic feet would that be?
I can do this and have done it for the heck of it, I took a box 12x12x12 inches, which is a cubic foot,
filled it with packing peanuts the tried to fill a 1 Gallon container, that amount almost fills a 1 gallon
bucket twice.
I even ask a math teacher and was told that 1 cubic foot equaled 7.481 gallons,
then I said that is liquid, teacher ansered yes, then i ask what about dry and got
a response of I do not know. Answered by Harley Weston. 





Sides and vertices 
20071117 

From derek: What is the correct name for a 2D geometric shape that would look like one slice from a round pizza and how may sides and vertices would it have? I believe you would say it has one vertex and two sides with the curved boundary not resulting in vertices or a side. Your help is much appreciated. Answered by Chris Fisher and Walter Whitelty. 





How many centimeters equal one meter? 
20071115 

From Sherrie: How many centimeters equal one meter? Answered by Penny Nom. 





The third side of a triange 
20071112 

From Christine: I need the inequality to describe the third side of a triange if two sides are known. First side is 23 and second side is 15. What is the third side? Answered by Stephen La Rocque and Victoria West. 





A mole of hydrogen peroxide 
20071111 

From John: i need to get a mole of hydrogen peroxide, which i know is 34g, but i don't have a way to measure grams, so do you know how many mililiters i need to have 34g of hydrogen peroxide. Thanks for all the help Answered by Stephen La Rocque. 





How do i convert milliliters to grams for water and also for copper sulfate (CuSO4)? 
20071111 

From jenn: how do i convert milliliters to grams for
water and also for copper sulfate (CuSO4)? Answered by Harley Weston. 





KWH and MWH 
20071110 

From Julie: Please provide the conversion of MWH to KWH or viceversa. thanks Answered by Penny Nom. 





Cubic centimeters to cubic yards 
20071110 

From Logan: if i have 188.4cm^3 of concrete how do i change it into cubic yards? Answered by Penny Nom. 





Related Rates (streetlamp and shadow) 
20071109 

From Casey: A street light is mounted at the top of a 15ft pole. A man 6ft tall walks away from the pole at a rate of 5ft per second. How fast is the tip of his shadow moving when he is 40ft from the pole? Answered by Stephen La Rocque and Penny Nom. 





Increasing and decreasing for functions 
20071109 

From David: Direction: Identify the open intervals on which the function is increasing or decreasing.
f(x)=1/(x^2)
f'(x)= 2/(x^3)
i understand how to get up until there, and the undf. is x=0, but now i'm having problem setting up the number table chart. i cant remember how, and where to place the increase and decrease +  the
chart, for example <0> where would the increase and the decrease be place? Answered by Harley Weston. 





Meters per second to miles per hour 
20071108 

From Niecey: If Greg was timed at 0.91 seconds for 10 meters running the 100 meter dash, at that speed, could he pass a car traveling 15 miles per hour in a school zone? Answered by Penny Nom. 





Why is the number 1 neither prime nor composite? 
20071108 

From amarilis: why is the number 1 neither prime nor composite? Answered by Penny Nom. 





Changing units and sizes of things 
20071108 

From Carol: volume of cube = 216 cubic inches how do I calculate cubic feet and calculate its surface area in square feet.
a rectangular box has dimensions of 3 x 6 x 15 how do I calculate surface area in square yards and calculate volume in cubic inches. if I double the dimensions how does it affect the volume Answered by Stephen La Rocque. 





Simple interest 
20071108 

From Lee: If a bank pays 3% simple interest anually on savings, and you did not take any money out of your account, how much money would you have deposited to earn $45 in interest Answered by Stephen La Rocque. 





Two triangles 
20071108 

From Barbara: If the base of a larger triangle is 34 inches long, what is the length of side A of the smaller triangle?
(the small triangle has on top the letter a on the right side of the triangle it has the letter b, and at the bottom of the small triangle it has the number 17) Answered by Penny Nom. 





I have a piece of material 44 inches by 78 inches 
20071102 

From Marianne: I have a piece of material 44 inches by 78 inches. How many linear yards can I get from it? Answered by Penny Nom. 





A decimal to a fraction 
20071101 

From Lisa: i am trying to turn a decimal into a fraction. my example is to turn 10.5 into a fraction at its lowest form Answered by Penny Nom. 





A wiffleball field 
20071031 

From Svitlana: The Adam's family has set up a wiffleball field in their backyard. The bases are arranged like a typical baseball diamond, where the distance between consecutive bases is the same. First base is opposite of third base, and second base is opposite of home plate. The distance between consecutive bases is 50 feet. Now, the pitcher stands 25 feet from home plate and lies on the line between home plate and second base. How far is the pitcher from first base? Round your answer down to the nearest inch. Answered by Penny Nom. 





Density 
20071030 

From Ali: Would an object sink or float in pure water if it has a mass of 10g and a volume of 5 cubic centimeters?
314 Answered by Stephen La Rocque. 





Constantly accelerated motion 
20071029 

From Priyanka: A, B and C are three points lying in that order on a straight line. A body is
projected from B towards A with speed 3 m/s. The body experiences an
acceleration of 1 m/s^2 towards C. If BC =20 m, find the time taken to reach C and
the distance travelled by the body from the moment of projection until it reaches C. Answered by Stephen La Rocque. 





Converting millimeteres to inches 
20071027 

From Alison: I am hoping to buy a cabinet, the measurements are 1120mm x 560mm, what is that in feet & inches. Answered by Penny Nom. 





The length of a rectangle is twice the width 
20071026 

From Tami: The length of a rectangle is twice the width. The number of square units in it's arear is four times the number of units in it's perimeter. What are the dimensions of the rectangle? Answered by Penny Nom. 





A sixfold increase 
20071024 

From Fred: If I have $500 and it grew to $3,000, what is the correct description of the increase? Is it a sixfold increase (sextupled), or a fivefold increase (quintupled)?
When I divide $3,000 by $500, the result is six, therefore, a sixfold increase? Answered by Stephen La Rocque. 





Converting bases 
20071024 

From Johanna: Is there an easy way to convert from base to base. For example, base 5 to base 9 or base 2 to base 4 etc Answered by Stephen La Rocque and Penny Nom. 





The nth term 
20071018 

From shannon: Ok , what i am having problems with is the nth term. I get how the numbers come together, but i am having trouble with finding the nth term. Answered by Penny Nom. 





Convert 13.5 oz per sq yard of fabric into grams per meter square 
20071017 

From marcy: I need to convert 13.5 oz per sq yard of fabric into grams per meter square. Answered by Penny Nom. 





Paying with silver  Part 2 
20071017 

From Shanna: The paying with silver problem. I understand how to do the problem, but could you please explain how you would use base 2 arithmetic to solve it. Answered by Penny Nom. 





Calculate the dimensions of the rectangle 
20071016 

From Sara: The perimeter of a rectangle is 62cm. The length of the diagonal is 25 cm. Calculate the dimensions of the rectangle. Answered by Stephen La Rocque. 





Surface area of an openended cone 
20071016 

From Lorne: What is the surface area of an open ended cone? Measured at 10' high,
16' diameter on the bottom and 2' diameter at the top. Answered by Stephen La Rocque. 





How many tons of asphalt are in 12 cubic yards? 
20071015 

From Matthew: I want to know how many tons of asphalt are in 12 cubic yards? Answered by Penny Nom. 





Four triangles in a square 
20071015 

From Kristina: A square with side lengths of 6 cm is divided into 3 right triangles and a larger isosceles triangle. If the three right triangles have equal area, find the exact area of the isosceles triangle. Answered by Stephen La Rocque. 





The dimensions of a rectangle 
20071014 

From Elizabeth: The perimeter of a rectangle is 20m. The area is 20sqm. Calculate the dimensions of the rectangle. Give your answers correct to two decimal places. Answered by Penny Nom. 





Substitution method 
20071011 

From Kevin: 3xx+2y=36y=11 Answered by Stephen La Rocque. 





Area of a quadrilateral 
20071010 

From Courtney: how would i find the area of a quadrilateral..
the sides are a (/) is 6cm, b (—) is 9 cm, and c (\) is 7 cm..
the angle between a and b is 140 degrees and b and c is 115 degrees.. Answered by Stephen La Rocque. 





Parabolic suspension bridge 
20071009 

From Jessica: A suspesion bridge with weight uniformly distributed along its length has twin towers
that extend 75 meters abouve the road surfce and are 400 meters apart.The cables are
parabolic in shape and are suspended from the tops of the towers. The cables touch the road
surface at the center of the bridge. Find the height of the cables at a point
100 meters from the center. (Assume that the road is level.) Answered by Stephen La Rocque. 





Simplifying algebraic expressions 
20071009 

From Sakeena: (2^2*3)^x+1/2^2x*3x Answered by Stephen La Rocque. 





Simplifying rational expressions 
20071009 

From Bama: x(x2)+1 divided by x^23x+2 Answered by Stephen La Rocque. 





Subtracting rational expressions 
20071009 

From Pamela: Subtract:
6p w __ 4c + p
w 4 w 4
Answered by Stephen La Rocque. 





Area and side length of a hexagonal tent 
20071009 

From Mark: Trying to buy a tent with 6 sides, in the catalog they give me sq. ft., what is the distance from side to side of a hexagonal tent with an area of 90 sq. ft. Answered by Stephen La Rocque. 





Coin jar 
20071007 

From a student: Sally empties his jar of coins. It contains $3.75 in nickels, dimes, and
quarters. The number of dimes is twice the number of nickels and the number
of quarters is three less than the number of nickels. Determine how many nickels,
dimes, and quarters were in the in the jar. Answered by Stephen La Rocque. 





Solving four simultaneous equations (system of four linear equations) 
20071007 

From Johan: I need some help in solving this question
x + 2y  3z + 4w = 12
2x + 2y  2z + 3w = 10
0 + y + z + 0 = 1
x  y + z  2w = 4 Answered by Stephen La Rocque. 





Motion along a line 
20071002 

From Claudette: If the position function of a particle is x(t) = sin^2(2t), find the distance that the particle travels from t = 0 to t = 2 Answered by Harley Weston. 





3 times x to the power 2 
20071001 

From Jennifer: The problem is 3 times x to the power 2.
I was just supposed to simplify, and I have no idea how. Answered by Penny Nom. 





I have a 6 digits 
20070928 

From Kim: I have a 6 digits. My hundredthousands digit is 1 less that my ones digit, 8 more than my thousands digit, twice my tens digit, and 4 times my hundreds digit. My tenthousands digit is 0. What number am I? Answered by Stephen La Rocque. 





Nine dots 
20070925 

From al: Connect the dots.
There is nine dots, three across and three down.
Connect the nine dot with the pencil only using four line and never lifting the pencil off of the paper. Answered by Stephen La Rocque and Harley Weston. 





Exponential regression 
20070924 

From Anonymous: I need help in finding this. Find a formula for exponential regression.
Determine how to calculate a and b in the formula.
Y = ba^x
where y is as a function of x. Answered by Penny Nom. 





A 3 ounce piece of gold 
20070924 

From Helen: What would the volume (in mL) of a 3 ounce piece of gold be?
16oz= 1lb
1lb= 454oz.
first i converted 3oz to lbs and then to grams to get the mass. i got 85.125 g.
now i don't know how to get the density to get to the volume. Answered by Stephen La Rocque. 





Finding equations, intersection point of two lines at right angles 
20070922 

From Yaz: Find the equation of the line joining A(1,9) to B(6,120). Another line passes through C(7,5) and meets AB at rigth angle of D. Find the euation of CD and calculate the coordinates of D. Answered by Stephen La Rocque. 





Metres per minute to miles per hour 
20070920 

From Angela: If a person is traveling 150 meters per minute, what is their speed in miles per hour? Answered by Stephen La Rocque and Harley Weston. 





(5C squared + 14C + 11) divided by (5C + 4) 
20070920 

From John: (5C squared + 14C + 11) divided by (5C + 4) Answered by Harley Weston. 





Area of an irregular lot 
20070920 

From Joanne: I found your web site through ask.com & it's great. Really hoping you can help me. We are looking at purchasing an existing home with a lot size that is advertised at 2.04 acres, however, even with my limited math skills I know this is not correct.
Their calculation takes the deepest part of the lost (179 feet) multiplied by the widest part of the lost (497.26 feet) as if it was a perfect rectangle. As you can see from the faxed diagram it is far from rectangular in shape.
Can you advise as to the true lot size? As I mentioned we are looking at this property as a purchase so time is of the essence.
I have also faxed this information (with the diagram) to the number listed on your web site. Thank you so much for your help. Answered by Harley Weston. 





how do you simplify 3a + 13b = 37 
20070916 

From brandon: how do you simplify 3a + 13b = 37 Answered by Penny Nom. 





Volume, mass and density 
20070914 

From Nathan: I have a sample of material that is 10cmx10cmx5cm and has a mass of 29 grams. How many grams would a sample of the same material that was 96cmx188cmx5cm be? Answered by Penny Nom. 





How much stone will be needed to fill the trench? 
20070914 

From Debbie: A trench 100metres long 1ft wide*18inches deep with a 4inch pipe laid. How much stone will be needed to fill the trench.
How much weight in stone would I need to fill it? Answered by Penny Nom and Victoria West. 





Is it platinum or silver? 
20070914 

From Jordan: In Chemistry we are doing a lot of problems that are much more math related than anything. One of my questions reads: A certain medallion has a mass of 55.64 g. When placed in 75.2 mL of water in a graduated cylinder,
the water level rises and then reads 77.8 mL.
Is the medallion made of platinum (D=21.4 g/mL) or silver (D= 10.5 g/mL)? Answered by Penny Nom. 





The contents of a silo 
20070914 

From Steven: I need to know how to find the weight of the contents of a silo that is 4 feet across and is funnel shaped at 60 degrees Answered by Penny Nom. 





Composite angles 
20070913 

From Gilbert: what is a composite angle? please help Answered by Stephen La Rocque. 





What was the water level in the cylinder? 
20070911 

From glen: After a 5.63g sample of Wood's metal has been added to the water in a 10mL graduated cylinder, the new water level is 8.7mL. What was the water level in the cylinder before the sample was added? Answered by Stephen la Rocque. 





Markup to include 6% commission 
20070907 

From Steve: I estimate the cost to build a house for $250,000.00. I mark it up by 20%:
$250,000 x 1.20 = $300,000 base price (BP) without sales commission. I want to set
the sale price (SP) to include a 6% commission to pay the real estate fee. After the
6 % fee is paid I want to net the $300,000 base price. The formula is basically:
$300,000 + 6% of SP = SP. But I can't figure out how to solve for SP. Answered by Penny Nom. 





2x+1+x4+4x+1 
20070906 

From laurie: 2x+1+x4+4x+1 Answered by Penny Nom. 





How many two digit numbers contain at least one 7? 
20070906 

From Janet: How many two digit numbers contain at least one number seven? Answered by Penny Nom. 





Variable expressions  part 2 
20070904 

From lisa: how do I write a variable expression for word phrase example x less than =
2 or 2 less than p
4 fewer than job please help Answered by Penny Nom. 





Variable expressions 
20070904 

From Eric: how so i write a numerical or variable expression for each quantity.
example two dozen eggs or d dozen eggs
number of quarts ub a 3 gallons Answered by Penny Nom. 





16x^2+4xy^2+8x divided by 4xy 
20070902 

From Ricardo: how can i solve that problem of polynomial division?
16x^2+4xy^2+8x divided by 4xy Answered by Penny Nom. 





The quotient of thirty and ten times a number. 
20070902 

From Jenna: I need help on How to translate a phrase into an algebraic expression:
The quotient of thirty and ten times a number. Answered by Penny Nom. 





george, thomas, abe, alexander... 
20070901 

From lori: george, thomas, abe, alexander...
come up with the next few
im confused and need help!! Answered by Stephen la Rocque and Harley Weston. 





Similar triangles 
20070829 

From James: Question: In the triangle ABC, X is a point on AC. AX = 15 m and XC = 5 m. The angle AXB is 60 degrees and the angle ABC is 120 degrees. Find the length of BC.
I am sure to an extent that this has to do with similar triangles, but I am not certain. Answered by Harley Weston. 





Converting a repeating decimal to a common fraction 
20070822 

From isabelle: how do you turn 6.333... into a fraction in simplest form? Answered by Stephen La Rocque and Penny Nom. 





More on the sixth degree equation 
20070821 

From Farzan: Equation 1 :
(R + (6.67*5.98*10^13/((R^2)*2)))^2  (R^2) = (7.27*(10^5)*R)^2
Equation 2 :
(6.67*5.98*10^13/(R^2*2))^2 + 6.67*5.98*10^13/R = (7.27*10^5*R)^2
As you see if we expand the left part of the first equation and simplify, the
equations become same, but these two equations have different answers in my
math software.The first one has 3 amounts for R, but the second one has 6
amounts. Why are the answers different ? Answered by Stephen La Rocque. 





A sixth degree equation 
20070820 

From Farzan: Dear friends
I need to solve this equation with an understandable method for highschool students :
(6.67*5.98*10^13/(R^2*2))^2 + 6.67*5.98*10^13/R = (7.27*10^5*R)^2
please solve this problem if you have time. Answered by Harley Weston. 





The area of a five sided lot 
20070819 

From Karyn: I have been looking at your site, but I am still confused as to how to
figure out the exact square footage of my irregular lot (since it is a gradual fan
lot from the front, and triangles out in the back). Answered by Harley Weston. 





What is 240mL of water in cups? 
20070816 

From Gareth: What is 240mL of water in cups? Answered by Penny Nom. 





Angle of depression to a football 
20070815 

From Tosin: The angle of depression to a football from the top of building 10m high
is 17 degrees. Find the distance of the ball from the foot of the building. Answered by Stephen La Rocque. 





Division by decimals 
20070815 

From Brooklyn: I am studying for an exam, and I will not be able to use a calculator. I can not figure out how to do division is the number on the outside of the box is a decimal. Ex: 2/6.3=X Can you please help me figure this out? Answered by Penny Nom. 





The length of the third side of a triangle 
20070815 

From Brooklyn: What is the equation to find the length of the third side of a triangle if you have the length of A, B, and the angles(s)? Answered by Stephen La Rocque. 





The tension in a single strand of wire 
20070813 

From Gene: Seeking an equation that calculates the tension in a single strand of wire or rope. Conditions: the wire is fixed at both ends, A known weight is suspended from the center of the span. The weight will dipslace the strand downward some distance Y. Let the distance between the fixed ends be X= 500mm. Weight W=0.5kg. Original tension in the strand is T= 10 newtons.Your help sincerely appreciated. Answered by Gabriel Potter and Stephen La Rocque. 





Water bill woes 
20070812 

From Terry: I know that a cubic foot of water=7.48051945 gals., but I keep getting my water bill and they go by thousands of a gal. per cubic foot. Is there a conversion that says that shows this? Water department=.763 x cubic foot used=thousands of gallons water used that month. Exampel: 72cu. ft meter reading x .763+ 58. galons of water I use in a month. Total 58=thousand = +gallons. This is wrong. There are only two people in the house. Answered by Stephen La Rocque. 





The swaying of a building in the wind 
20070811 

From San: During a strong wind, a tall builing, such as the CN Tower, can sway
back and forth as much as 100cm, with a period of 10 seconds.
Please help me to determine the equation for this function, in the form
y=asinkx Answered by Stephen La Rocque. 





Induction  divisibility 
20070804 

From Jerry: How would you prove that for any positive integer n, the value of the expression 3^(2n+2)  8n 9 is divisible by 64. Answered by Chris Fisher and Penny Nom. 





Rolling a metal plate 
20070731 

From k.a.suresh: How to calculate the plate size for rolling (2010mm OD)plate thick is 6mm Answered by Harley Weston. 





Subdividing a property into half acre parcels 
20070731 

From Pamela: We need to divide a large property with five sides and strange angles into 1/2 acre parcels from the top down. We want to know where along the eastern and western borders of the large property to make the divisions. Answered by Stephen La Rocque. 





Vehicle collision 
20070731 

From Tania: If a driver falls asleep at the wheel of a newer model car and slams into
the rear of a parked classic mustang (28603280lb) and the parked car
is thrown 100 ft across the street, what would be the minimum speed
required by the newer car in order to move the mustang? Answered by Penny Nom. 





320 acre lots 
20070729 

From melisa: we are splitting a 320 acre parcel into five 35 acre lots with one 145 ace lot. I have the footage of each side there are eight:
5280 x 2640x2640then out1320x1320up x2640back inx1320upx1320this now would meet back to the 5280foot side i know there is a half of a square mile and 320 acres.what would the measurements be in feet for length to make a square or a rectangle to make a 35 acre lot? Answered by Harley Weston. 





Angle of depression 
20070723 

From joyce: hello,
here is my problem......
As you stand on a bridge w/c is 100 ft. above the water
you are looking @ an approaching barge.
If the A of top of the front of the bridge is 29.04 degrees
and the angle of depression of the rear is 17.36 degrees .
Find the length of the barge? Answered by Harley Weston. 





f(x) = (x^4)  4x^3 
20070722 

From Michael: I'm a student who needs your help. I hope you'll be able to answer my question.
Here it is: Given the function f(x)=(x^4)4x^3, determine the intervals over which the function is increasing, decreasing or constant. Find all zeros of f(x) and indicate any relative minimum and maximum values of the function.
Any help would be appreciated. Thank you for your time. Answered by Harley Weston. 





Angle of depression (declination) between sailboat observations 
20070718 

From Joyce: From a cliff 150 ft above a lake, we see a boat sailing directly towards us.
The angle of depression of the boat is seen to be 5 degrees and 7 inches and
11 degrees and 18 inches. Find the distance sailed between observations. Answered by Stephen La Rocque. 





The area of a property 
20070717 

From Mary: I currently have an opportunity to sell my property to a business and they would like me to send a proposal to them with details.
I need to know the square footage of my property and have tried using your formula from similar questions. The dimensions of my property are as follows
front line facing street: 19.908 m
right side : 37.338 m
back line : 29.779 m
left side : 43.983m
The front line and the right side are at right angles to each other. Can you formulate and reply? Thank you Mary Answered by Harley Weston. 





Sample size 
20070717 

From Nurse: If a population has standard deviation 20, what is =
the
minimum sample size to be 95% confident that the error should be =
accurate to
within 4? Answered by Harley Weston. 





Radical 96 plus radical 27 divide by radical 3 
20070717 

From linda: radical 96 plus radical 27 divide by radical 3 Answered by Penny Nom. 





Trig functions for angles not between 0 and 90 degrees 
20070716 

From Tim: My question: Why is the value of a trigonometric function, the same, for an angle over 90 degrees and its reference angle?
How are the angle and its reference related? Do they both form a triangle that has equal sides? Answered by Penny Nom. 





The two towers (angles of elevation trigonometry) 
20070714 

From joyce: The angle of elevation of tower B from the top of tower A is 28 degrees
and the angle of elevation of the top of tower A from the base is 46 degrees
Find the height of tower A if tower B is 120 m high? Answered by Stephen La Rocque. 





Any regular polygon inscribed in a circle 
20070712 

From DJ: Circle with r=12" is inscribed in a regular octagon. What is the length of each octagon segment?
Note: Our answer works for any regular polygon inscribed in any circle. Answered by Stephen La Rocque. 





Converting measurements 
20070711 

From Nicole: if you have 8 oz of water how many cc: will there be. Answered by Stephen La Rocque. 





The probability of rolling double sixes twice in a row 
20070710 

From Matt: what is the probability of rolling double sixes twice in a row? Answered by Stephen La Rocque. 





Grams of vodka 
20070710 

From Andrew: milliliters to grams..vodka 80 proof? Answered by Stephen La Rocque. 





Derivative of a Function 
20070709 

From Bob: What is the derivative of the function a sub n = [n/(n+1)]^n ? Answered by Stephen La Rocque. 





Proof that any side of a triangle is less than half the perimeter. 
20070707 

From Omkar: Any side of a triangle is smaller than half of its perimeter, prove this in short ? Answered by Stephen La Rocque. 





Finding the radius of an inscribed circle 
20070705 

From Maria: I need to find the radius of a circle which is inscribed inside an obtuse triangle ABC. I know all the angles and all the lengths of the triangle. Answered by Stephen La Rocque and Chris Fisher. 





Tons of concrete 
20070703 

From Trey: I have 300,000 square feet of concrete and want to know how to convert this to tons? Answered by Harley Weston. 





A statistical difference 
20070703 

From a student: I am writing a paper for a grad class in which I am comparing achievement levels of boys and girls. I have data that shows the average marks for girls and boys in each grade 12 subject for the entire province.
My prof want me to show there is a statistical difference. What do I have to do to show this? I don't have access to the raw data, so don't know the SD. Is there anything I can do mathematically with the data that I have? (I can determine n for each set of data, it ranges between 2400 and about 13000 for each subject area.) Answered by Chris Fisher and Harley Weston. 





Expansion on a steel boat 
20070628 

From JOHN: that is the expansion on a steel boat that is 300' long by 100' wide.
if the water temp is 72deg f. and the deck temp is at 150deg f.
I think the deck would grow in all dir. and by what dist? do I still use
0.00000645 Answered by Stephen La Rocque. 





How do I convert milliliters(powder form) to grams? 
20070628 

From ed: How do I convert milliliters(powder form) to grams Answered by Harley Weston. 





How do I convert inches to mm in my head? 
20070627 

From philip: Hi, I would like to know how to convert inches to mm in my head, I use socket sets and want to know an easy way to work out what 3/16, 7/32 is in mm. Thanks Phil Answered by Harley Weston. 





sinx and cosx 
20070625 

From Mac: Can anyone tell me whether sinx and cosx is differentiable at x=0 ?
As far as i know, cos(x) and sin(x) is differentiable at all x. Answered by Penny Nom and Stephen La Rocque. 





Volume in a triangular water trough 
20070624 

From David: A water trough has sloping sides of length 500mm making it triangular in cross section, with vertical ends. The width at the top is 600mm and the length is 2.0 metres.
(i) Calculate the capacity of the trough, giving your answer accurate to the nearest litre.
(ii) Find out the depth of the water when the trough is half full. Answered by Stephen La Rocque. 





Average speeds 
20070622 

From Dee: A guy goes 3.1m a second for 29 seconds in a golf cart. He then walks 1.5 meters a second. How long does he have to walk to get the average speed of 2.1m a second? Answered by Stephen La Rocque. 





Simplify 
20070621 

From A student: what is the answer of
3y+5/2(4y+1)+5y/2 Answered by Penny Nom. 





Simultaneous equations : the Elimination method 
20070621 

From Patricia: I need to find the value of X and Y using the Elimination method.
5/x + 3/y=4
25/x2/y=3 Answered by Stephen La Rocque. 





New wood siding 
20070620 

From Angela: I have a trailer that is 14x70 and I took off the wood siding that was about 8 feet tall. They want $8.60 a cubic yard.
How many cubic yards do I have and how much will it cost me. Thanks to all! Answered by Stephen La Rocque and Penny Nom. 





Making a box with a particular volume 
20070620 

From Kimberly: How do you convert 487 cf into box? Answered by Stephen La Rocque. 


