







A lock combination 
20220719 

From Kendal: If I tried I could probably (I think) figure the answer but it would take a minute and I hoped maybe as math people there may be a simple formula… I just watched a new movie Black Phone, the kid is given 5 numbers for a combination lock in order but with no indication where the stops are. The numbers (in order) are 23317, my question is how many possibilities with a standard combination lock are there…ie. 23317, 23317, 23317…. As you can imagine not a great movie…my curiosity may get the best of me depending on how your app works ;). Thanks for your time. Answered by Penny Nom. 





Strings of letters 
20220425 

From Javar: How many different combinations can I make with A 12 selection list but only
using A&B
Example:
A,B,A,B,A,B,A,B,A,B,A,B
A,B,B,A,A,B,B,A,A,B,B,A
B,B,A,A,B,A,B,A,B,A,A,B Answered by penny Nom. 





The length of a line at 45 degrees 
20220409 

From Aiden: Let's say one line is diagonal and one line is vertical.
If they eventually meet at a 45 Degree angle,
How long will the diagonal line be compared to the vertical line?
(For Example: If The Vertical Line is Exactly 1 Inch. Answered by penny Nom. 





sec(pi/12) 
20220323 

From Diana: Please help me find the exact value of the following trigonometric expression:
sec(pi/12). Thanks! Answered by Harley Weston. 





A word problem 
20220129 

From Ric: Box of oranges weighs 9 pounds. 2/3 of oranges eaten. Box and
remaining oranges weighs 4 pounds. What is weight of box when
empty? Answered by Penny Nom. 





The next rational number 
20220114 

From Sophia: what comes after 3 1/2? Answered by Penny Nom. 





A graph with 100 vertices and one edge 
20220111 

From Maftuna: A graph has 100 vertices and only one edge. How many connected components does it
have? Answered by Penny Nom. 





A Word Problem 
20211217 

From Bryson: Yolanda, Brian, and Charlie have a total of in their wallets. Brian has less than
Yolanda.
Charlie has times what Brian has. How much do they have in their wallets? Answered by Penny Nom. 





The height of a right triangle 
20211215 

From Slash: hi how can i find the height of a triangle from the hypotenuse and base. please
go into some details with some steps because it is hard to understand. thanks Answered by Penny Nom. 





Simplifying a complex expression 
20211215 

From Grace: Write in the form. a+bi,
67i+8i^2+4i35i^4 Answered by Penny Nom. 





Roll of film 
20211120 

From Brian: Trying to create a formula to calculate the build up on a roll of film is calculated. Except instead of of a roll, it's essentially a rectangle with two semicircles on each at the end.
Example: I start with a 6" diameter core on each side, and I start winding .005"
thick film on the core. The distance between the center of those cores, length of the inner rectangle is 7.125.
If I continue to do this for a total length of film of 3000 feet, what will the
roll length and width be.
So what I need is the formula to perform this type of calculation.
Can you help me? I want to be able to plug the formula in a spread sheet and to be able to input a core diameter, a film thickness and a total length and the length between the center of the two cores(which is the inner rectangle's length I'm assuming).
Thanks Answered by Harley Weston. 





The sides of a 5pointed star inscribed in a circle 
20210918 

From Scott: Is there a calculation for the length of each side of a fivepointed star?
I am not worried about area but if I have a circle with a 7.5 foot radius and
place a star inside it, how can I measure the lines creating the star? Answered by Harley Weston. 





The dimensions of a rectangle 
20210909 

From Ash: I need to know how to figure out the dimensions of a rectangle. I know that the
area is 30ft and the perimeter is 26ft. I'm 15 and I have no idea what I'm
supposed to do. Answered by Harley Weston. 





30 % off 
20210907 

From Corrine: When I am shopping for clothing that is for sale, the advertisement may say the item is 30% off. The original price was $70. How much would it now be? (how do I figure that out?) Thank you! Answered by Penny Nom. 





The units digit of a square 
20210904 

From Aarzu: Sorry this may be a dumb question but how do you find possible unit digits of a
perfect square Answered by Penny Nom. 





An arithmetic and a geometric sequence 
20210829 

From Moti: Let {an} be an arithmetic sequence such that its 1st, 20th, and 58th terms are
consecutive terms of some geometric sequence. Find the common ratio of the
geometric sequence. Answered by Harley Weston. 





Fibonacci numbers 
20210825 

From John: Make a single column of numbers. Start with two numbers of your choice.
The third number is the sum of the previous two, the fourth number is the sum of
numbers two and three, and so on until
you have ten numbers in the column. Add up all ten numbers. Now, take the
seventh number and multiply it by eleven. This product will equal the sum of the
ten numbers. The same result will occur regardless of the first two numbers
chosen.
The question is why does the 7th number multiplied by 11 always equal the sum of
the ten numbers? Answered by Penny Nom. 





A word problem 
20210728 

From Isaac: The average mass of a group of children is 50 kilograms. Todd, who has a mass of
62 kilograms, then joins the group. This raises the average mass of the group to
52 kilograms. How many children were in the original group Answered by Penny Nom. 





New pool liner 
20210714 

From Kareena: I have a rectangular prism shaped pond that are 4ft by 8ft by 2ft. My pond is
lined on the sides and bottom with a pool liner so that it doesn't leak (the top
of the pool does NOT have a liner). I am redoing my pool and would like to
increase the size of the pond. Each dimension will increase by the same amount,
and the size of the pool liner will double. How much I am increasing each
dimension of the pond? Give an exact answer and than an approx. answer rounded to
the nearest tenth. Answered by Penny Nom. 





How many ways can you travel from A to D? 
20210702 

From shawn: Hello, I am trying to solve a problem which is how many ways can you travel from
A to D. A has 4 options b has 3, C and you get to D. How many ways are there? Answered by Penny Nom. 





3.1 miles in 4 minutes 
20210621 

From Jean: I am a school bus driver. My route directions and time schedule have me traveling
3.1 miles in 4 minutes. How fast do "they" expect me to drive to accomplish this?
Thank You Answered by Penny Nom. 





UFO speed in MPH from nearest galaxy in one year 
20210522 

From Joe: If the next closest galaxy is 15 quadrillion miles away and there are 8760 hours
in one year; how fast would a UFO have to fly to travel from the next
galaxy, in MPH in one year ?
Google calculator gives this result: 1.7123288e+12
I don't understand what the "e+12" means.
How is that pronounced, ex. trillion, quadrillion etc..?
Answered by Harley. 





The diameter of an octagon 
20210522 

From Sue: What is the diameter of an octagon with 8 foot sides Answered by Penny Nom. 





The height of a cone 
20210513 

From Carmen: If a cone has a slant height of 25 inches and a radius of 7 inches what is the
height in inches of the cone? Answered by Harley Weston. 





2.5 percent of 1.5 billion 
20210513 

From Anish: What is the 2.5 percent of 1.5 billion?
please state if there are any general formulae of this calculation.
Thank you Answered by Penny Nom. 





An octagonal drum 
20210511 

From Louie: I teach carpentry on an Indian reservation.
My students want to make an 18 inch drum frame.
They want to have 8 sides or an octagon shape to the drum frame.
What angle I have to set my miter saw to cut the angles to fit the octagon together.
I want to use this formula by changing the diameter of the frame.
Answered by Harley Weston. 





More on a roll of paper 
20210507 

From Stephen: Can you help with the equations to calculate the length of paper required to
achieve a target outside diameter when wrapped around a core please?
The inside diameter of the cardboard core is 76mm
The thickness of the wall of the cardboard core is 5mm
The thickness of the paper is 138microns
The desired outside diameter of the finished roll is 320mm
I hope you can help me with a solution, Thank you Answered by Harley Weston. 





Word problem 
20210507 

From Donelle: Freddy is three times as old as Mary. Mary is twice as old as Jack. Jack is 11
years old. How old is Freddy? Answered by Penny Nom. 





The maximum area of a garden 
20210428 

From Lexie: suppose you want to make a rectangular garden with the perimeter of 24 meters.
What's the greatest the area could be and what are the dimensions? Answered by Penny Nom. 





The volume of a spherical bowl 
20210423 

From Danny: How many gallons of water in a glass bowl with the dimensions of 10 inches high
and 13.5 inches wide? Answered by Penny Nom. 





Rates & Ratios 
20210411 

From Kenneth: Is it correct to think that a rate can have units that are the same? Usually
rates have units that are different to each other. Answered by Penny Nom. 





Four friends in a race 
20210406 

From Angel: Four friends ran a race:
Ben finished seven seconds ahead of Mike.
Noel finished three seconds behind Sam.
Mike finished five seconds behind Noel.
What will be the formula to support their place? Answered by Penny Nom. 





Time, distance and rate 
20210310 

From Zander: A lady drives 180km from her wine farm to Ceres. On her return (at night) she
drove 30km/h slower. Her return takes one hour longer. At what speed did she
drive home? Answered by Penny Nom. 





Bearing and distance 
20210222 

From bahlqees: A girl starts from a point X and walks 220m on a bearing 063°.she then walks to a
point Y on a bearing 156°.if Y is due east of X,calculateXY solve and
draw the diagram please Answered by Harley Weston. 





Scale drawing 
20210210 

From Elias: a football field is 160m long and 120m wide .
Find the distance between its opposite corner flag posts .
use the scale of 1cm:20m Answered by Penny Nom. 





Division in different bases 
20210206 

From Promise: Simplify the following 302 in base6 divided by 5 in base6 Answered by Penny Nom. 





Multiplying and adding two numbers 
20210206 

From Yvonne: Two numbers multiplied to get 13 and added to get 12 Answered by Harley Weston. 





Simplify 
20210205 

From Leslie: To simplify improper fractions, do you convert it to a mixed number or leave as an improper fraction? My daughter had a quiz in which she was supposed to simplify her answers. So, for example, on one question the answer she got was 11/10 and on another question she came up with 17/12. The teacher marked these as incorrect because they were mixed numbers. Her teacher wrote on her paper, "**name**, I even gave this back to you and told you to go through and simplify your answers!" We (her father and I) feel that the teacher wanted her to convert her answers, not simplify them but I haven't been able to find a definitive answer online. So, does simplifying improper fractions mean converting them to mixed numbers? Thank you for your help! Answered by Penny Nom. 





A scale factor 
20210202 

From Layla: Beth planned to travel from Battery Park to Times Square. The distance between the two places is 2.48 inches on the map of New York City. If the scale factor used for the map was 1 mile = 0.4 inch, find the actual distance between the two tourist attractions. Answered by Penny Nom. 





Arranging chairs in a row 
20210126 

From aiyana: hi i need help with this a teacher wants to arrange 16 chairs in a equal rows in his class room Answered by Harley Weston. 





A scrambled word 
20210119 

From john: How many ways can you scramble the work "0axaca" if two a's must never be adjacent? Answered by Penny Nom. 





A scenario for a linear equation 
20210119 

From raven: I have to create a scenario for the following equation y=1x+45
and then find what each part of the equation represents Answered by Penny Nom. 





Velocity and acceleration 
20210109 

From yen: The motion of a stone projected upward is given by the relation s=112t  16t^2.
What are the values of velocity and acceleration when t=3 sec? Answered by Penny Nom. 





A 2.5 acre square 
20210109 

From hannah: how many feet of fence needed to fence a square 2.5 acres?? Answered by Penny Nom. 





10^1,000,000 
20201218 

From G: Looking for the name of a really big number.
its a 1. with a Million zeroes after it. Answered by Harley Weston. 





0^(a+bi) 
20201203 

From Douglas: I realize raising 0^a = 0 if a>0 and undefined if a<=0.
If have read that 0^bi is undefined for all b.
What I don't understand is why 0^(a+bi) = 0 if a and b are not equal to zero.
Is this purely by definition or is there a logical reason why this is the case?
(I have taken Complex Analysis, so have a fairly good understanding of complex numbers.) Answered by Penny Nom. 





Comparing two job offers 
20201117 

From Selena: Raja has been offered two jobs.
Each of these jobs takes 24 weeks to complete.
One job pays $3440 every 8 weeks. The other job pays $2700 every 6 weeks. Raja wants to accept the job that pays more per week.
Show how to use equations to help Raja make her choice. Answered by Penny Nom. 





The distance between opposite vertices in an octagon 
20201114 

From joe: If the dimension from one flat part of an octagon to opposite flat is 500 mm what is the largest diameter (point to point) of the octagon? Answered by Harley Weston. 





Golf for 28 golfers over 4 days 
20201114 

From David: hi, I was wondering if you could help me with a golf draw, I have 28 players and wish to play a four round foursomes over 4 days
I would like to minimize the amount of games that they play together. Answered by Harley Weston. 





Divisibility by 8 
20201110 

From Sariyah: Of the positive integers between 1000 and 10000 that are divisible by 8, how many have a 5 in the hundreds place? Answered by Harley Weston. 





The dimensions of a rectangle 
20201102 

From Chie: A rectangular piece of property has an area of 987m² and a perimeter of 136m. Find its LENGTH and WIDTH. Answered by Penny Nom. 





Running around a circular track 
20201031 

From kaylee: Keiko and Kendra are training for an international track competition. Kendra is running one lap on the outside of a circular track with a diameter of 1000 feet. Her constant rate of speed is 12 mi/h. Keiko is running one lap on the outside of a nearby circular track with a diameter of 1125 feet. She is also running at 12 mi/h. Find the time, in minutes, each runner needs to complete one lap. Answered by Harley Weston. 





Equivalent fractions 
20201031 

From Lexi: Which of the following fractions is equivalent to 84 / 90?
A. 14 / 15
B. 42 / 45
C. 14 / 15
D. 42 / 45 Answered by Penny Nom. 





An analytic proof that a quadrilateral is a parallelogram 
20201026 

From Apollo: Prove analytically that if ABCD is a parallelogram in which points P and Q trisects the diagonal AC, then BPDQ is a parallelogram. Answered by Penny Nom. 





Two equations with fractions 
20201022 

From mia: I am supposed to look for x and y. my teacher didn't explain very well. please help : ((
2x  y = 5
x/4 + y/3= 2 Answered by Penny Nom. 





2xy = 2x*2y 
20201022 

From Amber: Um i am wondering what this equation equals. Thank you for your time and help.
2xy=2x*2y Answered by Penny Nom. 





Solving an inequality 
20201018 

From nunya: 3(4 + 2n) > 2n  16 Answered by Penny Nom. 





A word problem with three variables 
20201018 

From Yesenia: Carmen, Austin, and Trey have a total of $128 in their wallets. Trey has $10 more than Carmen. Austin has 4 times what Trey has. How much do they have in their wallets? Answered by Penny Nom. 





A confusing problem 
20201001 

From Kgaugelo: a triangle has the vertices A(4;3),B(x;y)and C(2;1). Determine the coordinates of B if the equation of the line BC is y=5x9 Answered by Harley Weston. 





A combination lock 
20200929 

From Rourke: how many possible combinations are there in a 4 digit lock with 6 numbers
which can repeat themselves. Answered by Penny Nom. 





Factoring an interest formula 
20200929 

From Kenneth: Hello
P + Pr has a common factor of P so it can be expressed as P(1 + r) after the P is factored out..
How does the "P" get in front of (1 + r)?
P/P + Pr/P = 1 + r What step is used to show that P is added in front of (1 + r)?
I thank you for your reply. Answered by Harley Weston. 





Is 1 an odd integer? 
20200927 

From Nicole: is 1 an odd integer? Answered by Penny Nom. 





The height of a tree 
20200927 

From Kerissa: A man height 1.2 m standing on top of a building 34.6m high views a tree some distance away he observes that the angle of depression of the base of the tree is 35 and the angle of depression of the top of the tree is 29, assuming that the tree stands of level ground. Determine the height of the tree. Answered by Penny Nom. 





A Parabolic Arch 
20200921 

From Malen: A hotel entrance makes a parabolic arch that can be represented by the quadratic function, y= x^28x+24, where y is the height of the arch and x is the distance from wall to wall in the feet. What is the distance between the two walls of the arch. Answered by Harley Weston. 





my prcentage of years on earth is 
20200921 

From Bill: This Tuesday is my birthday and I will be 69. and I just wanted to know
life ear is say earth is 6 billion years old I'm just curious to what percentage does my existence on earth reptresent I do realize that it's a
flash in the pan Answered by Penny Nom. 





A problem involving distance, time, and rate. 
20200915 

From Ruby: Amy drove on the highways at 70 miles/hour to pick up fruits from her grandma’s garden in the morning.
She stayed there for two hours. When coming back in the afternoon, she drove on the local roads at 40 miles per hour to avoid traffic.
She spent a total of 8 hours for this trip, and drove a total 300 miles.
How many miles did she drive each way? Answered by Penny Nom. 





The surface area of a dome 
20200913 

From Sue: i need to know the outside square footage of a dome house 24ft
across at the bottom and 16ft high so i know how much
paint it will take to cover it. Answered by Harley Weston. 





9 games with 3 possible outcomes 
20200913 

From Daniel: Hi
I’d like to know how many different outcomes would be in a
Soccer week played if there is 9 different games 2 teams and 3 outcomes
Win, tie or lose
Thank you Answered by Penny Nom. 





Simultaneous equations 
20200905 

From Paa: a+b=8
a+c=13
b+d=8
cd=6
find the value of each letter Answered by Penny Nom. 





Slope 
20200904 

From Mark: I'm trying to calculate slope over 157'.I have a drop of 9 1/8 inches. What fraction of an inch of fall do I have every 10 feet Answered by Penny Nom. 





The angular speed of a wheel 
20200903 

From Catrina: A car is moving at a rate of 75 miles per hour, and the diameter of its wheels is 2.6 in. Find the angular speed of the wheels in radians per minute. Answered by Penny Nom. 





Bearings 
20200830 

From Tom: A boy walks 5km due North and then 4km due East
I. Find the bearing of his current position from his starting point
II. How far is the boy now from the starting point Answered by Penny Nom. 





4 digits to unlock a padlock 
20200828 

From Sophie: I have forgotten the order in what the numbers go for my padlock! The numbers are, 0125, they don't have any repeats like, 0001, 0002. What are all possible the combinations? Help! Answered by Penny Nom. 





Arranging buttons in a row 
20200824 

From Nick: A sequence of 10 buttons can be arranged in a line. The buttons are identical except for colour, with each button being either red, blue or green.
Arranging buttons in a row
How many sequences can be made where there are exactly 2 red buttons as part of the sequence of 10 buttons?
How many sequences can be made where there are exactly 4 red buttons as part of the sequence of 10 buttons? Answered by Penny Nom. 





A diameter of a circle 
20200819 

From Apple: One end of the the diameter of the circle with equation x^2+y^24x+4y=2 is (3,1). Find the coordinates of the other end of the diameter. Answered by Penny Nom. 





A window problem 
20200818 

From Richard: Hello,
I was hoping your math specialists could help me with some formulas.
I have shapes with specific known variables need to calculate others.
Example:
We make a straight legged arch, This shape has a width a overall height and a leg height, The leg height is always less then the overall, And the top is arched.
We have the width, Height, and leg size.
Need to calculate the length of the curve and sq ft of the shape. Answered by Harley Weston. 





A word problem with no algebra 
20200811 

From Julie: At 3pm, Bruce headed north at 30 km/hr. 2 hours later, Lucy headed south at 40 km/hr. At what time will they be 340 km apart Answered by Penny Nom. 





More on the last 2 digits of a^k = N 
20200807 

From Jay: I've seen solution methods for finding the last 2 digits
of a^k = N, where a and k are known. My question
is:
What if the number N is known and the last 2
digits are, say, ...62. Is there a way to find, for
any given a, the value of k which will result in a
number where the last 2 digits are ...62? and if
that is possible, then do the same for
a number with the last n digits (say 7 or 53 or
something)? Answered by Harley Weston. 





Filling holes with stone dust 
20200730 

From Zach: I’m looking for amount of stone dust needed for thirteen holes with
a 3ft depth and 12in diameter with a 4x4 post. I would need the
measurement in KG. Answered by Harley Weston. 





A tank, 5/9 full of water 
20200728 

From Nat: A rectangular tank contains 1200cmsquare of water when it is 5 out of 9 full . Its base area is 80cmsquare . Find the height of the tank. Answered by Penny Nom. 





Five rational numbers between 4 and 3 
20200728 

From Priyanshi: Five rational numbers between 4 and 3 Answered by Penny Nom. 





x+sin(x) 
20200724 

From adm: f(x)=x+sin(x)
to evaluate f(30)
use radians only or degrees Answered by Harley Weston. 





Choosing 4 balls from 9 
20200722 

From sandiso: What is the probability associated with each possible random sample of size 4 from the population consisting of these nine balls Answered by Penny Nom. 





why percents can be helpful 
20200702 

From THERESA: why percents can be helpful Answered by Penny Nom. 





4sin(2x)cos(2x)+1=0 
20200702 

From Sheila: 4sin(2x)cos(2x)+1=0 Answered by Penny Nom. 





Some strings of 4 digits 
20200626 

From Judy: I wrote previously and need more help. I need to generate a list of 4 digit. Numbers using 09 with no repetitions
I know that there is a 6 followed by a 2. Order does matter
Thank you in advance for your help. Answered by Penny Nom. 





Scale factor 
20200626 

From Kinza: Hi, my question is The perimeter of a triangle is reduced from 75cm to 20cm. What is the linear scale factor? Answered by Penny Nom. 





A word problem involving linear equations 
20200622 

From Allie: The length of a rectangular swimming pool is p m and its width is q m. Its given tht the length of the swimming pool is twice its with. if the perimeter of the swimming pool is 150 m, find the values of p and q
this is in the chapter linear equations Answered by Penny Nom. 





A word problem with fractions 
20200621 

From Sthantsa: I'm stuck with this question, I don't know where to begin because
i really don't Know where to start.
Jessie and Thulani each has a sum of money. Jessie’s amount is 2/5
that of Thulani’s. If Thulani were to give Jessie R198, then his
remaining amount will be 6/8 that of Jessie’s amount.
How much does Jessie have originally?? Answered by Penny Nom. 





1 square cm is 100 square mm 
20200619 

From macie: explain why the conversion factor for cm squared to mm squared is 100 ,and not 10 Answered by Penny Nom. 





390 as a percentage of 800 
20200618 

From Yug: What percentage is 390 grams of 800 grams? Answered by Penny Nom. 





The substitution method 
20200610 

From Hardebolar: simultaneous equation by substitution method
.ab=2/3 a+b=1 2/3 Answered by p. 





Working backwards 
20200605 

From Jill: Emma has a bunch of grapes (1)/(2 ) of it she gave it to her friend and (3)/(4 ) of the remaining grapes she gave it to Gina. There are 4 grapes remaining. So how many bunch of grapes to begin with? Answered by Harley Weston. 





An octagonal pool deck 
20200530 

From lauchie: need help on cut sizes and cut degrees on octagon pool deck for a 24 foot round pool Answered by Harley Weston. 





Percentage profit 
20200530 

From jaheem: A shopkeeper buys an article for 80cents and sold it for $1. Calculate the percentage profit. Answered by Penny Nom. 





A hexagonal planter 
20200528 

From Callie: Hello, I'm having trouble cutting my angles for my 2 x 4 planter. I did exactly as I've watched and read and mine is just not turning out! Ok, so I want 6 or 8 piece hexagon. With an interior of about 10". So I understand that the boards can be any length, but its the 30 degree or 22 1/2" angles that matter. So. How do I figure how long my 2 x 4 is with 6. and another 8 pieces of 2 x 4 to make this planter and at what angle. So does the length determine the angle? Thank you in advance! i don't want to waste anymore wood! And how to figure length, angle and center circumference? Answered by Harley Weston. 





10 of 24 hours as a percentage 
20200527 

From Larzy: what is 10 of 24 hours in percentages Answered by Harley Weston. 





Are all quadrilaterals the same? 
20200527 

From eva: are all quadrilaterals the same? Answered by Penny Nom. 





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. 





A sand castle in the shape of a truncated cone 
20200523 

From Summer: A sand castle is in the shape of a truncated cone as shown. Calculate the length of the diameter of the base.
The diameter of the top of the truncated cone is 20cm
The height is 30cm
The slopes are 32cm Answered by Penny Nom. 





A 50:1 ratio in a pint 
20200522 

From Steve: How much oil do I need to put in a pint if it's 50:1 ratio Answered by Harley Weston. 





Drawing a counter from 2 bags 
20200521 

From Sephy: Question 4: Two bags, 1 and 2, each contain equal size counters.
Bag 1 contains a pink counter, yellow counter and white counter.
Bag 2 contains counters labelled 1, 4, 5 and 7.
A counter is drawn at random from bag 1
and a counter is drawn at random from bag 2.
If the counter from bag 1 is pink, the number on the
counter from bag 2 is increased by 1
If the counter from bag 1 is yellow, the number on the
counter from bag 2 is decreased by 5
If the counter from bag 1 is white, the number is halved.
Find the probability of scoring a number below 3 Answered by Penny Nom. 





Forming the largest cylinder 
20200520 

From Amanda: How do I find the maximum surface area and volume of a cylinder made up of ONE 8.5x11 piece of paper? Answered by Penny Nom. 





Maximizing the volume of a cone 
20200518 

From Ella: Hello, this is question  'If you take a circle with a radius of 42cm and cut a sector from it,
the remaining shape can be curled around to form a cone. Find the sector
angle that produces the maximum volume for the cone made from your circle.' 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. 





How long will it take to dig the trench? 
20200506 

From Marielena: If the production rate for hand digging a trench is 1.2 mh/cy, how long would it take for one man to dig a trench 2 feet deep by 1 foot wide by 216 feet long? Answered by Penny Nom. 





Three numbers have a sum of 45 
20200506 

From Jayden: Three numbers have a sum of 45. The greatest of the 3 numbers is 2 greater than the least number. What are the numbers? * Answered by Penny Nom. 





The flight of a football 
20200506 

From Michael: Football is thrown from a 10yard line. It reaches its highest height of 20 yards. It lands on the 50yard line after 2 seconds. What is the equation of the parabola that models this throw? I really need help as I've been on this for the longest amount of time. Answered by Penny Nom. 





Signs at 1/3 mile intervals 
20200503 

From Heather: The butterfly garden in St. Thomas gardens is a three mile loop at every 1/3 there is a sign along the loop to mark each 3rd of a mile along the loop if Melanie is standing next to the 7th sign at what mile is she? Answered by Penny Nom. 





The volume of a stone 
20200502 

From KHOSI: A rectangular container is 9cm wide,17cm long and contains water to a depth of 11cm. A stone is placed in the water and the water rises 2,2cm .Find the volume of the stone Answered by Penny Nom. 





The volume under an an uneven surface 
20200501 

From Solon: I am trying to fill an area of floor which has an uneven surface. I need to know the volume of fill.
If you imagine a rectangular room (4 corners) that measures 189 inches by 240 inches and the depth at each corner is different.
Let us say corner #1 has a depth of 1", corner #2 has a depth of 0", corner #3 has a depth of 2" and corner #4 has a depth of 4".
How would i find the volume of said floor area?
Any assistance would be greatly appreciated! Answered by Harley Weston. 





Adding a service charge and the VAT 
20200430 

From richard: was given a figure by a client been performance bonus of staff , the figure is 806,698.35 from this 806,698.35 is my company service charge of 10% and 5% of the service charge will be Vat to government in summary from 806,698.35 is 10% of service charge and 5% of service charge is the VAT Answered by Penny Nom. 





A system of equations. 
20200427 

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





Power notation 
20200426 

From Aditi: The power notation of 1 / 128 Answered by Penny Nom. 





The width of a rectangle of land 
20200426 

From Teresa: If a rectangle shape piece of land is 813 feet long. How many feet width would be 2 acres? Answered by Penny Nom. 





How many boxes will fit in a closet? 
20200424 

From Jordan: Janelle has some boxes that are 43cm long, 23cm wide and 18cm tall.
She wants to store them in a closet in her basement that is 2.2m tall, 1.1m
wide, and 0.8m deep. What is the maximum number of boxes that
Janelle can possibly fit in the closet? Answered by Penny Nom. 





Building a house in one year 
20200422 

From Fify: If it takes 8 men to build a house in 450 days. How many men would it take to build the house in 365 days? Is there a specific method to calculate this please? Answered by Penny Nom. 





Four digit numbers starting with 6 
20200422 

From Judy: I need to generate a list of 4 digit numbers using 09 where the first digit is 6 and no numbers can be repeated Answered by Penny Nom. 





An arch in the form of a semiellipse 
20200420 

From Anggelica: an arch in the form of a semiellipse is 8 feet wide at the base and has a height of 4ft. how wide is the arch 1foot above the base? Answered by Penny Nom. 





Gravel for a French Drain 
20200417 

From Ray: Hello,
** I am wanting to add 2 French Drain's in my yard. The 1st drain will be 25 ft. long, 8 in wide and 18 in deep. The pipe I'm using is 4in. in diameter. I'm trying to figure out how many yards of clean gravel I will need for this project?
** The 2nd French Drain will be 100 ft in Length, 10in wide and 18 in deep. I will also be using the 4in in diameter pipe for this drain. I am needing to see how many yards of clean gravel, I'll need for this drain?
Any assistance would be greatly appreciated!! Thank you!! Answered by Harley Weston. 





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. 





An isosceles triangle 
20200416 

From jo: Find the angle between the two sides of length 5 in an isosceles triangle that has one side of length 9 and two sides of length 5. Answered by Penny Nom. 





Why is a square a rectangle but a rectangle is not a square? 
20200415 

From A parent: Why is a square a rectangle but a rectangle is not a square? Explain your answer. Answered by Penny Nom. 





Two chords 
20200414 

From Frank: How to find the length of the radius of a circle if you know the lengths of two chords Answered by Penny Nom. 





A hexagon constructed from two triangles 
20200413 

From sunny: Triangles AEC and FDB are equilateral triangles and EA= DF= 12cm. The polygon
at the center of the star is a regular hexagon. What is the area of the hexagon? Answered by Penny Nom. 





A rectangular garde 
20200410 

From Denise: In a rectangular garden a person says "if I made that bed 2 feet wider and 3 feet longer it
Would have been 64 sq,ft bigger. But if it had been 3 feet wider and two feet longer
It would have been 68 sq.ft bigger.
What is the length and width of the garden bed? Answered by Penny Nom. 





Three consecutive odd integers 
20200410 

From Roxie: What is three consecutive odd integers? Answered by Penny Nom. 





Setting up a linear equation 
20200410 

From Jessie: Michaela and Aleah play on the same basketball team. In one game, Michaela scored
one fifth of the teams points and Aleah scored one tenth of the teams points. Together,
they scored a total of 42 points. How many points did the team score?
I can't figure out how to put together the equation with the given variables. I have to show the work and I also need to know how to make
that kind of equation. Thanks! Answered by Penny Nom. 





A pond in a garden 
20200409 

From Jin: c) I have a large square pond set inside a square garden: both the pond and the
garden have sides which are a whole number of metres, and outside the pond,
the garden is grassed over. The area covered by grass is 188 square metres.
Find the area of the pond. (5 marks) Answered by Penny Nom. 





Form a square and a triangle from a wire 
20200408 

From Raahim: 2. A 2 meter piece of wire is cut into two pieces and once piece is bent into a square and the other is bent into an equilateral triangle. Where should the wire cut so that the total area enclosed by both is minimum and maximum? Answered by Penny Nom. 





A 5 digit number 
20200404 

From Rajesgy: Guess the 5 digit number
Hint:
Number is divisible by 2
Average of all numbers is 5
Last 2 digit is divisible by 7 and the number is less than 50000
Only one odd digit Answered by Penny Nom. 





An arithmetic sequence 
20200404 

From ally: 10 ... last term 35 common difference is 3
(a) find the number of term in the sequence.
i have lost the formula. Answered by Penny Nom. 





A linear system 
20200402 

From Dadzie: x+s=8→1
y+x=13→2
yp=6→3
s+p=8→4 Answered by Penny Nom. 





A stemandleaf plot with decimals 
20200402 

From Renee: I am an AP Statistics student who is reviewing for the exam.
On one of my review worksheets, we have to create a stemandleaf plot for values with 2 decimal places (i.e. 9.14, 8.14, 8.74, 8.77, 9.26, 8.1, 6.13, 3.1, 9.13, 7.26, and 4.74).
How would I make the stemandleaf plot for this? I've already searched your database and nothing popped up.
If you could help me, that would be great. Thank you! Answered by Penny Nom. 





A circle in a square 
20200402 

From Sabra: Hello, I have twins in the 7th grade that are learning how to find
circumference of circles. I am struggling with figuring out how to
help my children to find the answer to this question:
Tye has a square piece of yellow felt that has an area of 81
square inches. She wants to cut the largest circle possible from the
material to create a sun for her art project. What is the area of the felt
circle? Use 3.14 for pi. Round to the nearest hundredth if necessary.
I wasn't sure if I am to find the area of the circle through finding the
area of the square or what steps we needed to follow to find the
answer. Once I can see how one is worked out stepbystep, I
usually can help them along with questions that are similar. Answered by Penny Nom. 





Four digit combinations from 13480 
20200326 

From nancy: Good evening. I'm in a quandry. Can you help? I would like to know what 4digit combinations can be derived from 13480 no repetitions Answered by Penny Nom. 





The center and radius of a circle 
20200325 

From Riley: so it says find the center and the radius of the below circle
x^2+(y6)^2=121
i need help learning how to solve this Answered by Penny Nom. 





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. 





Aaron and Bill's ages 
20200312 

From Heather: My granddaughter had this third grade math problem. Aaron is 4 times as old as his brother Bill. In ten years Aaron will be twice Bills age. What are their ages? Answered by Penny Nom. 





Sixdigit telephone numbers 
20200312 

From Lulamile: What is the probability that a sixdigit telephone number has no repeated digits? The telephone number cannot begin with a zero Answered by Penny Nom. 





A times table in base 5 
20200311 

From Felix: Design a time table for numbers 110 in base 5 Answered by Penny Nom. 





Is there an equation to find what percent of 0 is 1? 
20200309 

From Asher: Question: Is there an equation to find what percent of 0 is 1.
I remember learning quite a long time ago that the answer inst 0 and it isn't infinity. I'm pretty sure it was something like %=0 approaching infinity or %=1 approaching infinity. And I know it depends what value you assign the numbers i.e. dollars or temperature. Furthermore, is asking "what percent 1 dollar is of 0 dollars" the same question as "what percent profit do you make from selling something worth 0 dollars for 1 dollar."
Thank you for your time and consideration
Asher Answered by Penny Nom. 





Sam and Claudia go on a bike hike 
20200303 

From Christie: Sam and Claudia start at the same time on a bike hike of 150 miles. Sam travels 3 miles per hour faster than Claudia and finishes the trip 8 1/3 hours before Claudia. At what rate in miles per hour does Sam travel? Answered by Penny Nom. 





Covering 1 acre, 6" deep 
20200302 

From Jim: How many cubic yards does it take to cover 1 acre 6" deep.
Thank you Also, can you show me how you determined that answer. Answered by Penny Nom. 





Fireman Fred needs to stay fit 
20200302 

From Chamundeswari: How do I explain this problem to a year 3 kid?
Fireman Fred needs to stay fit for his job. He runs 4.5km, 4 mornings, a week . if it takes him 4 minutes and 15 seconds on average to run 1km, how much time does he spend running over 4 weeks? Answered by Penny Nom. 





The volume of a berm 
20200228 

From jason: how much dirt is in an 20'w 12't 1350'l berm Answered by Penny Nom. 





A straight line graph 
20200226 

From Penehafo: I have a problem of drawing a straight line graph by the equation y=2x1 Answered by Penny Nom. 





The height of an isosceles triangle 
20200223 

From Reagan: I need to find the height of an isosceles triangle with a base of 6 and sides of 4 units. How do I find it? Answered by Penny Nom. 





Degrees, minutes and seconds 
20200221 

From Jonathan: If a cone has an angle of 22 degrees, when i place it flat on a surface, the new resulting central angle is now at 68.69123834, but how come when i saw it on my friend it say 68 degree and 40 minutes, what is this minute? Answered by Penny Nom. 





30% profit 
20200220 

From Sidra: A car dealer bought a car for £7500 and sold it for 30% profit.
For how much did he sell the car? Answered by Penny Nom. 





Multiplication base 8 
20200219 

From Tamesha: Let’s count with the symbols 0,1,2,3,4,5,6,7 (base 8)
A). Create a multiplication table for this base
B). Compute the following products using the multiplication algorithm
I). 7605 times 3713
II). 63725 times 40627 Answered by Penny Nom. 





The volume of a cylinder 
20200212 

From Mack: I need to find how close the actual volume was of a cylinder (with both ends closed)
to being optimized. Can you please send step by step response?
Height = 11cm
Circumference = 24.4cm
Thanks,
Mack Answered by Penny Nom. 





Sipping juice from a Tetra Pak 
20200211 

From Anjhelic: Karen is sipping juice from a 1 in. by 3 in. by 6 in tetra pack at the rate of 0.5in³/sec. How fast is the height of juice in the pack decreasing? Answered by Harley Weston. 





The area of a triangle from two angles and a side 
20200210 

From Chinmoy: How to measure the area of a triangle with two angles and length of the included side known? Answered by Harley Weston. 





A parabolic arch 
20200206 

From icyy: how high is the parabolic arch of span 20 feet and height of 16 feet, at a distance 5 feet from the center?
what equation will I be going to use? thank you 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. 





What was the original price? 
20200201 

From Gracie: If you buy something for $6.30 and it’s 30%off what was the original price? 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. 





Translation by a vector 
20200130 

From Jude: M(3,2) is the image of the point M under a translation by the vector (5,2). Find the coordinates of M Answered by Penny Nom. 





A question about fractions 
20200126 

From Awotile: A fraction whose denominator is more than the numerator is double when the numerator is increased by 6 and the denominator is increased by 5 find the original fraction? Answered by Penny Nom. 





A point on a line 
20200125 

From Samved: The line 3x/5  2y/3 + 1 = 0 contains the point (m, 2m1). Calculate the value of 'm'. Answered by Penny Nom. 





The volume of a coffee cup 
20200125 

From Amirah: What is the volume of a polystyrene cup with a height of 8cm, diameter of 5cm at the top and 4cm at the bottom when it is filled with water? Answered by Penny Nom. 





gcd(a^2 + b^2, a + b) 
20200119 

From Roger: I am stuck with this problem: find the gcd(a^2+b^2, a+b), where a & b are relatively prime integers not both zero. 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. 





The angle of a countersunk screw 
20200119 

From Barbie: I need to be able to verify the angle used for the head of a countersunk screw.
I have the diameter of the head, diameter of the shank and height between the
two. I assume it would be considered a frustum.
For example:
A standard 90 degree metric flat head screw in an M2 diameter has a head diameter of 3.65mm,
the actual thread diameter is 1.98mm and the height of the head is 1.20mm.
How can I prove that it is a 90 degree angle? Answered by Harley Weston. 





Investigating y = (2)^x 
20200113 

From Gonzalo: This is not precisely a maths question, but it is formulated based on my maths curiosity. Fidgetting with my new graphic calculator, I started graphing things and had the idea to graph $y=(2)^x.$
The result surprised me, and I thought a little bit about it, stored it on the back of my brain, and promised myself to look deeper into it someday. Answered by Harley Weston. 





What is the smallest 4 digit number? 
20200110 

From Ullas: What is the smallest 4 digit number? Answered by Penny Nom. 





The difference between two number is 7 
20200107 

From Jaypercey: the difference between two number is 7 find the two number if the larger 3times the smaller 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. 





The equation of a line 
20200105 

From coco: Good afternoon
If relationship between total cost and the number of units made it linear ,and if costs increases by 7$ for each additional unit made ,and if the total cost of 10 units is 180$ .
Find the equation of the relationship b/n total cost (Y) & number of unit made (x). Answered by Penny Nom. 





Dividing the tips 
20200102 

From Pat: trying to figure out division of tips I have 3 full time employees 40 hrs a week and 1 part time worker 12 hours a week what percentages do i give them to give them appropriate tips :) Answered by Harley Weston. 





A circle, a point, and a tangent line 
20191231 

From Faisal: A circle has radius 10 units and passes through the point (5,16). The xaxis is a tangent to the circle. Find the possible equations of circle? Answered by Penny Nom. 





Sabrina's age 
20191231 

From Nakyi: The sum of Sabrina’s age and twice her sister’s age is equal to their mom’s
Age. If Sabrina’s sister is two years older than her and their mom is 37, how old is Sabrina? Answered by Penny Nom. 





81^5 as a power of 3 
20191229 

From NA: How do we turn 81^5 into the power of 3? Answered by Harley Weston. 





A scale drawing 
20191228 

From Boris: If the scale drawing of a car park is drawn to a scale of 1cm representing 7m and the car is 133m by 93m, find the length of the drawing Answered by Penny Nom. 





Partitions of a set 
20191221 

From Ghani: 1. Are set partition "sets"?
2. If they are so then, why are both {{a}{b,c}} and {{a,b}{c}} said to be valid partitions of A ={a,b,c}
despite them having different elements?
(I understand that set are equal if they have the exact same elements).
Thank you! Answered by Harley Weston. 





10 miles in 2 minutes 
20191220 

From james: how fast would you be traveling to go 10 miles in 2 minutes? Answered by Harley Weston. 





Volume of a tree 
20191219 

From Maria: I have trees for sale. I need to calculate the volume of a tree from base which is wider than the stem.The base will be used for the making of hurleys, similar to hockey sticks so the wider base is crucial. Answered by Penny Nom. 





Odds 
20191216 

From Craig: I’d like to know what are the odds of a lotto machine giving out a specific 4 digit number as a quick pick?
I know there are 10,000 possible 4 digit combinations. So let’s say the number is 3587 what are the odds the lotto machine spits it out EXACTLY that way on a quick pick? Answered by Penny Nom. 





Input and output of a function 
20191216 

From Destanie: What is the output if the input is 1??? Answered by Penny Nom. 





Some questions about sets 
20191215 

From M.Azzi: Hello,
(I)  In set theory can a given set contain both elements and subsets, as "elements", as in :
A = {1,2,{},3,{{3}},8}
If yes :
1  then, is A = 6 ?
2  if the empty set is a subset of every set,
2. 1. does {} = {{}}, {{{}}} etc? , and if the is true what are the respective cardinals of the latter three? (0,1,1?).
2 . 2. Why isn't {1} equal to {{},1}? and why should these two be equal without having the same cardinality?
Sorry if my questions are not well expressed.
Thank you for the great service you provide. Answered by Harley Weston. 





More on lampshades from a cone 
20191214 

From Guy: from an earlier post re; lampshade from a cone
Being math ignorant I cannot figure out how this equation makes sense
\[\frac{2\pi \times 33  2\pi \times 20}{2\pi \times 33} = \frac{13}{33}\]
imagine these as fractions multiplied by 360 to calculate a section of a circle to form a cone
Thx Answered by Penny Nom. 





A function problem 
20191212 

From akash: if (2,1) is on the f(x), what is the coordinate of the corresponding point of 2(f(2x6)+5? Answered by Penny Nom. 





Guess and check 
20191211 

From Mariajosé: brian bought 98 stickers. the number of stickers per sheet was 2 times as large as the number of sheets. how many sheets did brian buy Answered by Penny Nom. 





The fencing needed for a square pasture 
20191210 

From Penny: I'm trying to calculate how many feet of fence I will need to fence a 4 acre square pasture. Answered by Harley Weston. 





Strings made from three characters 
20191210 

From Kelley: Hi,
I vaguely remember some formula for determining all the possible combinations of a set of numbers (or whatever).
If I have 3 numbers (0  2), then I have 0, 1, 2, 00, 01, 02, 10, 11, 12, 20, 21, 22, 000, 001, 002, 010, 011, 012, 020, 021, 022, 100, 101, 102 and so on.
What is the formula for determining all potential results?
Thank you!!
Kelley Answered by Penny Nom. 





The equation of a line 
20191210 

From Jourdan: Suppose a mining company will supply 96000 tons of ore per month if the price is 80 dollars per ton but will supply 70500 tons per month if the price is 20 dollars per ton. Assuming the supply function is of the form y = m x + b , find the slope, m and yintercept, b Answered by Penny Nom. 





Roll two dice and record the difference 
20191209 

From Barbara: Suppose you roll two dice 100 times. Each time you record their difference
(always subtracting the smaller one from the bigger one to get a positive
difference). The possible values you get are 0,1,2,3,4 and 5. You record
the frequency of each value in the following table:
Difference of two dice 0 1 2 3 4 5
Observed frequency 12 31 26 13 10 8
Let your null hypothesis be that the dice are fair, and the alternative
hypothesis be that they are not fair. Using a confidence level of α = 0.10,
test the null hypothesis by a goodnessoffit test.
Hint: begin by
completing table:
x 0 1 2 3 4 5
f(x) Answered by Penny Nom. 





Two people are clapping their hands 
20191206 

From Yukti: Two people are clapping their hands, but with different frequencies. Ramya claps her hands
17 times per 3 minutes, and Kumar claps his hands 31 times per 5 minutes. They start
clapping at the same time. How many times does each one clap before they clap together at
the same time again? Answered by Penny Nom. 





3/8 and 0.375 
20191205 

From Zamyiah: how does 3/8 turn into 0.375 i just don't understand it the question is hard. please answer in time thank you for your time. 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. 





Combinations of cities 
20191203 

From Oliver: Hi!
I'm looking to find out how many combinations (non repeating) there are for 6 cities.
If we name the cities A to F, possible combinations would include;
A.
A, B.
B.
A, B, C.
A, C.
B, C.
C.
and so on.
Thank you! Answered by Penny Nom. 





Two digit numbers 
20191203 

From Lacy: Using the digits zero through nine, how many twodigit numbers can be formed,which do not have a four or five? Answered by Penny Nom. 





The area and volume of a wedge 
20191130 

From Jasmine: what is the volume and surface area of a wedge with definition Answered by Penny Nom. 





An exterior angle of a parallelogram 
20191129 

From A student: one angle of a parallelogram is four times the measure of the exterior angle adjacent to it. find the interior angles Answered by Penny Nom. 





Caleb age and Juliet age add up to 25 years. 
20191122 

From tolulope: Caleb age and Juliet age add up to
25 years. eight years ago,Caleb was twice as old as Juliet. how old are they now. Answered by Penny Nom. 





The length and width of 1 1/3 acres 
20191122 

From Ben: I’m trading to figure out what the length and width of 1 1/3 of an acre
would be in a rectangle or in a perfect square Answered by Penny Nom. 





cos (3pi/2 x) 
20191120 

From sam: 1. express the following as a trigonometric function of angle x for cos (3pi/2 x)
the answer in the textbook is sin x but i am unsure of the process to get the answer. Answered by Penny Nom. 





A four person race 
20191119 

From Juvy: Ben finished seven seconds ahead of Mike.
Noel finished three seconds behind of Sam.
Mike finished five seconds behind Noel.
In what order did the friends finish the race? Answered by Penny Nom. 





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. 





Beginning algebra 
20191119 

From Maya: Two numbers have a sum of 57. Three times the first number is 13 less than the second number.
Find the numbers.
Use let statements to help you solve. (Grade 9 math)
Maya (help would be appreciated) Answered by Penny Nom. 





The product of 3 integers is 24 
20191106 

From Rick: This is a question on my sons preap practice quiz.
I think that there is information missing (?)
The product of 3 integers is 24
The sum of 3 integers is 12
What are the 3 integers ?
This is exactly how it was written on his quiz paper.
I have wasted to much time on the internet, trying to find a
formula(s) to help him.
Please help me. Answered by Penny Nom. 





The sum of the ages of Ruth and her mother is 77 years. 
20191106 

From Lydia: The sum of the ages of Ruth and her mother is 77 years. The difference in their ages is 27 years. How old is each? Answered by Penny Nom. 





Algebra 
20191106 

From Krizhia: How is y= 1/2 * (x1)² be x= √2y + 1. Please show me the steps Answered by Penny Nom. 





Bearings 
20191105 

From Deborah: three ships p q and r are at sea. the bearing of q from p is 30° and the bearing of p from r is 300°. if PQ=5km andPR=8km
I.illustrate the information in a diagram
II. calculate correct to 3sf the I. distance between Q and R. II. bearing of R from Q 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. 





Liza works for a call center 
20191031 

From Timothy: Liza knows that in the long term, she has a 65% chance of making a sale when calling on customers. One morning, he makes Six calls.
a. What is her probability of making three calls?
b. What is her probability of making sales fewer than three? Answered by Penny Nom. 





The divisors (aliquot parts) of a positive integer 
20191031 

From Kenneth: Is there a fast and simple method that can be used to determine the aliquot parts, whole, positive numbers that can divide into another whole, positive number? Answered by Harley Weston. 





Alex rents a car for one day 
20191031 

From Arshia: Alex rents a car for one day. The charge is $25 plus $0.20 per mile. Alex wants to spend exactly $110. How many miles can he drive? Answered by Penny Nom. 





The largest integer k so that that 3335^k is a divisor of 3336! 
20191029 

From Brandon: Hello my name is Brandon and I having difficulties in solving the following question: Given the number 3336! = 1.2.3.4........................3336 . What's the greater positive integer number k with the condition that 3335expk is a divisor of 3336!
Thanks for your help. Answered by Penny Nom. 





Even 5 digit palindromes 
20191024 

From daniel: How many palindromes of 5 digits are even? Answered by Penny Nom. 





The center of a circle 
20191024 

From Patrick: I'm trying to find a quick calculation to find the center of the circle that will touch the 3 points of an isosceles triangle.
Known dimensions are length of the triangle base and the height from the top point to the middle of the base.
Thanks in advance,
Kind regards,
Patrick Answered by Penny Nom. 





How many numbers from the set have the sum of its digits equal to 2? 
20191024 

From Marcel: Hello. My question is the following: Given the set {1,2...........10exp2019}, how many numbers from the set have the sum of its digits equal to 2?
I got some of them : 2 20 200 2000 20000 .......2. 10exp2018 11 110 1100 11000 110000....101 1010 10100 101000 1010000....10011 10010 100100 1001000 1010000.....10001 100010 1000100 10001000,,,,,,100001 1000010 10000100.......
My problem is that I have difficulty in finding a strategy to obtain the exact quantity of numbers. Please help me, thanks Answered by Penny Nom. 





The perimeter of a piece of a circle 
20191018 

From Arwin: The radius of a circle is 17 cm. A chord XY lies 9 cm from the centre and divides the circle into two segments. Find the perimeter of the minor segment. Answered by Penny Nom. 





The domain of f + g 
20191016 

From Angel: The domain of f+g when f(x)=8x+3 and g(x)=15x Answered by Penny Nom. 





How do you find the length and the width if all you had was area? 
20191016 

From Ali: So, How do you find the length and the width if all you had was area? 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. 





The difference of two numbers is 42 
20191014 

From Patrick: The difference of two numbers is 42 and the larger number is 8/5 of the smaller number. Find the two numbers. Answered by Penny Nom. 





Arranging 10 digits 
20191009 

From Laxmi: 1)The integers 0 to 9 are arranged along a straight line in some order.a) find a possible arrangement in which the sum of any three adjacent numbers is less than 15.b)is there an arrangement of this kind 0 is not included in the numbers. Answered by Penny Nom. 





A binomial probability question 
20191008 

From venni: The Medassist Pharmaceutical Company receives large shipments of aspirin
tablets and uses this acceptance sampling plan: Randomly select and test 24
tablets, then accept the whole batch if there is only one or none that doesn’t
meet the required specifications. If a particular shipment of thousands of
aspirin tablets actually has a 4% rate of defects, what is the probability that
this whole shipment will be accepted? Answered by Penny Nom. 





Four fours 
20191003 

From Irene: Using number 4, four times with any equation and the answer will be 2 and 5 Answered by Penny Nom. 





The binomial distribution 
20191001 

From PY: An online game called ‘Shop Quiz’ is held by an ecommerce platform, from Monday to Friday
every week. It consists of 8 multiple choice questions (MCQ) and each question has four options (A, B, C, D). Only one option is the correct answer. People who are able to correctly answer all 8
questions are winners and will be awarded a number of online shopping credits.
Let X represent the number of questions that a person can answer correctly in a ‘Shop Quiz’.
1) Explain why Binomial distribution might NOT be a suitable distribution for the random variable
X.
Mr. Saul likes playing the quiz, however, he is afraid that he might not have the necessary knowledge to answer the quiz questions. (The quiz questions cover a variety of topics including science, history, entertainment, sports and geography, etc.) Therefore, he tries to win the game by simply guessing the answers to each question. Answered by Penny Nom. 





Four less than three times a number is 20 
20190929 

From Linda: four less than three times a number is 20,what is the number? Answered by Penny Nom. 





Fractions and negative powers 
20190922 

From Will: 2/3 to the 6 power Answered by Penny Nom. 





Bearings 
20190922 

From Jean: X is due north of Y and 2km distant. Z is due east of Y and has a bearing of S35°12'E from X. How far, to the nearest metre, is Z from X? Will you help me solve this problem? Answered by Harley Weston. 





The volume of a fire hose 
20190918 

From Carlou: How many liters of water in a 2.5 inches diameter of fire hose with a 20 meters in length Answered by Penny Nom. 





4" x 4" square tiles 
20190918 

From Jill: how many 4" x 4" square tiles would I need for 50 square feet? Answered by Penny Nom. 





Why does the circle have a larger area? 
20190916 

From A student: given a circle and square of same perimeter, why does the circle have a larger area
I’m looking for an intuitive explanation rather than a computational one. Thanks Answered by Harley Weston. 





Mandy walks to work 
20190915 

From Kenneth: Mandy walks to work at a constant rate. Onethird of the way to work, she passes a bank.
Threefourths of the way to work, she passes a book store.
At the bank her watch reads 7:52 A.M., and at the book store it reads 8:02 A.M.
At what time is Mandy onehalf of the way to work? Answered by Harley Weston. 





A one foot rise in water level 
20190915 

From Stuart: If a lake were to rise one foot  how many linear feet would it spread onto the shore line ?
What is the correlation  1 foot of a rise = 10 feet onto the shore ? Does it depend on the lake
size  if so Lake Ontario in Canada. Answered by Penny Nom. 





The amount of concrete in a foundation 
20190911 

From Lorinda: How do you calculate ( in cubic yards) how much concrete is needed for the foundation of a rectangular building 40 ft by 85 ft if the foundation walls are 8 inches thick and 7 ft 6 inches high? Answered by Penny Nom. 





What is 5 squared? 
20190910 

From Pori: What is 5 squared? Answered by Penny Nom. 





The number of integers that satisfy some conditions 
20190910 

From Ryu: Using only the digits 0 1 2 3 4 5 6 7 8 9 without repetition, how many integers are:
(a) Greater than 999, less than 10,000, start with an even digit and are even?
(b) Greater than 999, less than 10,000, start with an odd digit and are odd?
(c) Greater than 999, less than 10,000, start with an even digit and are odd?
(d) Greater than 999, less than 10,000, start with an odd digit and are even? Answered by Penny Nom. 





Problem solving 
20190908 

From Arunsi: When a fifth of a certain number is added to 3 the result is 17. What is the number? Answered by Penny Nom. 





Vectors 
20190906 

From Kayla: Hi!
Due to time constraint issues, we skipped vectors in PreCalc last year. However, I'm attempting to complete my AP Physics summer homework and there are 3 problems with vectors. As I explained, I have no idea even where to begin and as such I need some help.
Problem 1:
A plane flying at 90° at 45 m/s is blown toward 0° at 62 m/s by a strong wind. Find the plane's resultant velocity.
I have tried all sorts of online calculators but none are providing me with a formula I can use to solve this problem on my own.
Problem 2:
If you walk 367 m North and 785 m West what is your total displacement from your original location?
What is the problem asking for when it says displacement?
Problem 3:
A plane travels on a heading of 127.0° at a velocity of 25 km/hr. What are the horizontal and vertical components of the plane's velocity?
As you know already, I have never done vectors so I don't know what horizontal and vertical components of velocity are.
Thank you So Much for your help!! I am struggling!!
 Kayla Answered by Penny Nom. 





Using the Laws of Exponents 
20190906 

From Samiya: i have been struggling with the laws of exponents so im having trouble with this question. the
question is to write (b*exponent2*c)(b*exponent5*c*exponent4*) Answered by Penny Nom. 





Average savings 
20190906 

From Puchu: A student was saving an average of £2 per week for 25 weeks. He then found a part time job and after total of 45 weeks his average savings rose to £9 per week
How much did he save over 20 weeks after finding job? Answered by Penny Nom. 





The volume of a berm 
20190906 

From John: I need to construct a berm:
8' tall
5' across the top
20' at the base
125' long
How much soil will I need Answered by Harley Weston. 





How was math created? 
20190903 

From Phu: How was math created? Answered by Harley Weston. 





A negative minus a negative 
20190903 

From Maggie: Why is a negative minus a negative a negative? Answered by Penny Nom. 





Can one equation with two variables be solved algebraically? 
20190830 

From Don: Can one equation with two variables be solved algebraically? 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. 





David Is 6 years older than his sister Delia 
20190827 

From Abigail: David Is 6 years older than his sister Delia. In 10 years the sum of There age 52. how old are David and Delia today Answered by Penny Nom. 





A flat top cone 
20190825 

From Mary: I want to make a paper model of a flat top cone with the radius of the base is 12.5 cm and the radius of the apex is 7 cm.The height is 15 cm and the radius of the apex is 5 cm. The height is 15 cm.
Can you help me with the angle and construction, please?
Thanks. Answered by Penny Nom. 





The length of half an acre 
20190823 

From Angeles: How many Feet Long In Half An Acre (Rectangle) Answered by Penny Nom. 





A problem with logarithms 
20190823 

From Iriogbe: Find the value : if log3 (a6) =2b and log2 (a7) =3b Answered by Penny Nom. 





The average height of a wall 
20190815 

From Jeff: Trying to figure the average height of a sloped foundation wall.
The lowest point is 24 inches or 2 feet.
The highest point is 116 inches or 9’ 8 inches.
Can this be figured without the degree of slope or can we assume it is
Equaled sloped from point a to point b. Thanks Answered by Penny Nom. 





The area of a shape 
20190814 

From Lymp: Hi, for math we are calculating the area of shapes and my teacher wanted me to research how to calculate the area of shapes so i was wondering if you could tell me how t calculate the area of any shapes. Please tell me how to calculate a cross, parallelogram and a polygon Answered by Penny Nom. 





A cone of maximum volume 
20190814 

From Refilwe: The slant height of a cone is 10cm. Determine the radius of the base so that the volume of the cone is a maximum Answered by Penny Nom. 





The radius of a circle of given area 
20190814 

From shelby: What's the radius of a circle that has an area of 803.84cm2? I also need examples of how you got the answer. Answered by Penny Nom. 





Conversing from tons to cubic yards 
20190803 

From Kathleen: Is there a simple formula to convert the following from tons to cubic yards:
Topsoil
Sand base
Fill dirt Answered by Penny Nom. 





Filling a hole 
20190801 

From Jackie: Filling a hole 25ft round 3ft deep how much dirt is needed? Answered by Penny Nom. 





A combination lock 
20190801 

From markbo: A combination lock has 09 plus Y on its keypad. A code is generated by selecting
4 digits from those keys (09 and Y) with no repeated choices,
but sequence does not matter
(i.e. 1234 is the same as 4321, and the same as 3412 and counts as one combination)
How many different 4digit codes are possible in this scenario? Answered by Penny Nom. 





Combination lock 
20190731 

From Antony: Hello.
So my 3yr old daughter has had a bit of a play with the 3 dial combination lock on my backpack and locked it closed.
I am looking for all the possible combinations to go through a process of elimination to find the combination she has set.
To be clear. There are three dials, each with the numbers 09. I have read 10x10x10=1000 options but not sure if that is correct .. feels too small?
Many thanks in advance. 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. 





The volume of a well 
20190730 

From Jordan: How much water could my well hold if the depth of the well is 30 feet
feet and the diameter of the well is 24 feet ? Answered by Penny Nom. 





A problem involving ratios 
20190724 

From Dhanendra: A plot reserved for playground in the ratio of length and breath 11:4 gram panchayt spends rupees 45000 for boundary at the rate of 100 per m. Find the dimensions of the plot. Answered by Penny Nom. 





Packing chocolates in boxes 
20190722 

From CHESKA: 1.levy can pack the chocolate bars either with 35 bars in a box,with 42 in a box, or with 49 in a box. what is the least number of chocolate bars that he has?
2. the blue light of a Christmas light blinks every 2 second. the red light blinks every 3 second and the yellow light blinks every 5 second. how many times will the three lights blink at the same tims in one hour?
3.a wooden straightedge can exactly measure an 825 cm rope, a675 cm rope, and 375 cm rope. what is the least possible length of the straightedge? how many times will it measure each rope? Answered by Penny Nom. 





Listing three digit combinations 
20190717 

From Larry: Using numbers 09, what are all the possible combinations of choosing 3 numbers regardless of order and no 3 numbers being used more than 2 times in the combination. So no 1,1,1, 2,2,2, 3,3,3 etc. Order does not matter. Could you please send me a listing of all those combinations? Answered by Penny Nom. 





Three digit codes 
20190714 

From Jessica: I need to find the total number of 3 digit codes using the digits 1 through 9. How many of these codes would be odd numbers, and how many even? Answered by Penny Nom. 





The maximum volume of a cone 
20190714 

From A student: find the maximum volume of a cone if the sum of it height and volume is 10 cm. Answered by Penny Nom. 





A three digit code 
20190714 

From Hannah: I have a briefcase with a threedigit code. I can set the code myself using digits 1 through 9, assuming that each digit can only be used once. How many possible codes are there? Answered by Penny Nom. 





Volume of a spherical cap 
20190712 

From Shanto: In a jar of water, we kept a sphere with radius r. Then 75% of its volume went under water. Find out the distance of the top of the sphere from the surface of the water. 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. 





Order of operations 
20190706 

From Carri: What is the answer (( 5 × 12) / 3 ) + 30  50 Answered by Penny Nom. 





Distance traveled 
20190703 

From J: If a fly flies at 15 feet per a second between two walls closing in upon themselves. Wall A is moving to the right at 3 feet a second and wall B is moving to the left at 15 feet a minute, how far will the fly fly before the walls touch? Answered by Penny Nom. 





Forty foot and 9 spacers 
20190628 

From Christopher: Ok I've got forty foot and 9 spacers one each end and 7 between what is the distance between the seven in the middle Answered by Penny Nom. 





One part in 10^x 
20190626 

From Jim: What is the meaning of the phrase ‘one part in 10x” where the x is an exponent? I have seen these examples: “...better than one part in 10x” and “...to within one part in 10x.” Answered by Penny Nom. 





The volume of a frustum 
20190624 

From Abdulganiy: A right pyramid on a base 10cm square is 15m high
a)find the volume of the pyramid
b)if the top 6m of the pyramid is removed what is the volume of the remaining frustum? Answered by Penny Nom. 





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. 





The area of a patio 
20190623 

From Miguel: Stephanie has 60 feet of metal fencing material to only fence 3
sides of a rectangular patio. A tall metal wall serves as the fourth side
of the rectangle. write a function for the area the garden (A) in terms
of width in feet (x) What measures of the width would give an area of
at least 150 feet? Answered by Penny Nom. 





The area of a triangle in acres 
20190623 

From Karen: if I have a triangle that measures 78 ft x 54 ft x 50 ft, how do I figure out what part of an acre that is?? Answered by Harley Weston. 





What are the next three terms? 
20190618 

From Shriya: 6, 2 , 2, 6,10 what are the next three terms? Answered by Penny Nom. 





A tube through a board at 45 degrees 
20190615 

From Guy: I need to insert a tube 5/8" diameter into a board at a 45 degree angle. What size hole must I drill for the tube to fit snugly? Answered by Harley Weston. 





The perimeter of 200 acres 
20190614 

From AARON: How many feet is the perimeter of 200 acres? 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. 





150 litres has been drawn from a tank 
20190612 

From Eke: When 150 litres has been drawn from a tank, it is 3/8 full, how many litres will the tank hold? 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. 





Finite and infinite sets 
20190610 

From Pretzie: What is Finite Set & Infinite Set? Answered by Penny Nom. 





Two power generators 
20190607 

From A student: At 100% efficiency two generators would produce 750 MW of power. At efficiencies of 65% and 75%, they produce 530 MW. At 100% efficiency, what power would each produce? Answered by Harley Weston. 





A car drives over a cliff 
20190606 

From Victor: A car was going 90 mph towards 90foot drop. What would the distance would the car travel horizontally ,from the cliff edge? Answered by Penny Nom. 





An inline lock with four rows 
20190605 

From Edward: I have a inline lock with four rows of numbers 09.The numbers cannot be repeated.
Can you please print the possible codes so I can go through them one at a time. The
lock and the cable cost $300. Don't want to pitch it. You guys are lifesavers, can't
wait to hear back. Thanks. Answered by Penny Nom. 





3 digits from 7 digits 
20190602 

From Corban: HOW MANY COMBINATION ARE THERE USING 3 DIGITS NUMBERS ONLY 17
ie 137 731 317 456 654 123 321 248 Answered by Penny Nom. 





How many lines of symmetry does a circle have? 
20190528 

From raji: how many lines of symmetry does a circle have??? Answered by Penny Nom. 





Compound interest 
20190528 

From Kenneth: Hello:
Is compound interest on $1.00 for one year the same as simple interest on
$1.00 for one year?
Compound interest would be $1.01, and I believe the same amount would be
the same at simple interest. Answered by Penny Nom. 





Maximize monthly revenue 
20190523 

From a student: A realestate firm owns 100 garden type apartments. At RM400 per month, each apartment can be rented. However, for each RM10 per month increase, there will be two vacancies with no possibility of filling them. What rent per apartment will maximize monthly revenue? Answered by Penny Nom. 





Two circles 
20190523 

From Arman: Two concentric circles have their centres at
point C. The radius of the smaller circle is
8 cm. The length of chord AB is 26 cm and
is tangent to the smaller circle. What is the
circumference of the larger circle? Answered by Penny Nom. 





Do all angles have to be equal to a number? 
20190515 

From Malik: Do all angles have to be equal to a number? By all angles I mean adjacent, vertical, supplementary, complementary. Answered by Penny Nom. 





What is the original price? 
20190515 

From Tyler: if 45% of an item is $90.00, then what is the original price Answered by Penny Nom. 





An 80 acre square 
20190511 

From Linda: How long and wide is an 80acre piece of land that is square?
How long and wide is a 160acre piece of land that is square? Answered by Penny Nom. 





Pennies, nickels, dimes, and quarters 
20190509 

From william: Ann has 177 coins (pennies, nickels, dimes, and quarters)
Her total value is $19.90
She has the same number of nickels as dimes.
She has the same number of quarters as dimes.
How many of each does she have? Answered by Penny Nom. 





Subdividing land 
20190509 

From Reuben: This is the measurements of my plot, AB 46.7M, BC 193.1, CD 198.5 & DA 208.25 (Clockwise naming of sides) angle A at 90 degrees. My questions is how do i subdivide this plot from the bottom having lines running parallel to CD, eg two 2acre plots. the the remaining part becomes my compound (Uper part at line AB) Answered by Harley Weston. 





The volume of a wall 
20190508 

From Peter: I’m building a dry stack stone wall which is 36” wide at the base, 42” tall and 24” wide at the top. What would be the volume for a 36” long segment ?
Thanks, Peter Answered by Penny Nom. 





Why Mean? 
20190508 

From Jill: A group of teachers were trying to figure out why the”mean” is called mean  do you know?? Answered by Penny Nom. 





Two numbers 
20190503 

From fds: The difference of two numbers is 2, and their sum is 4. What are the two numbers? Answered by Penny Nom. 





Volume and Surface area of a sphere 
20190503 

From Caitlin: Why does the surface area formula of a sphere have a squared radius while the volume of a sphere has a cubed radius? Answered by Penny Nom. 





A repeating decimal divided by a whole number 
20190501 

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





If 45% of an item is 90.00 
20190501 

From Gavin: If 45% of an item is 90.00 what is the original price? Answered by Penny Nom. 





A hemispherical bowl 
20190429 

From Innocent: Abc is the section through a hemispherical bowl centre O radius 15cm. It contains water whose maximum depth is 8cm. What is the width of the water surface? Answered by Penny Nom. 





A circle inscribed in a triangle 
20190428 

From Daksh: O is the centre of the inscribed circle in a 30°60°90° triangle ABC right angled at C.
If the circle is tangent to AB at D then the angle COD is Answered by Penny Nom. 





A dot on a child's car wheel 
20190428 

From julia: A wheel of a child’s car revolves at 10 rpm. A painted dot on the circumference of the wheel is 12 cm from the centre of rotation of the wheel. How far does the dot travel in 5 s, to one decimal place? Answered by Penny Nom. 





The length of an arc 
20190428 

From Patrick: If an arch is 48 inches wide at the base and 30 inches tall at its apex, what is the length of the arch? Answered by Penny Nom. 





A thread around a cylinder 
20190428 

From Ally: A cylinder has a diameter of 3.5 cm. How many times will a thread 143mm go round the cylinder? Answered by Penny Nom. 





Two linear equations with a fraction 
20190426 

From Asha: 2x=3y …1
x2+4/3(y+1) ...2
note: … is equation Answered by Harley Weston. 





Constructing a hexagonal pyramid 
20190425 

From REBECCA: I'm doing a project for my Honors Geometry class and I have to build a regular hexagonal pyramid. I was given the volume of .75 gallons, but I don't know how to figure everything else out. Please help?
Thanks,
Rebecca Answered by Harley Weston. 





Three friend's ages 
20190425 

From Lemicio: Janet is 10 years older than Karin, who is twice the age of Josef. If their combine age is 55, how old is each one now? Answered by Penny Nom. 





80% of an item is $200.00 80% of an item is $200.00 
20190425 

From kayla: if 80% of a item is $200.00 what is the original price Answered by Penny Nom. 





Is every rectangle a rhombus? 
20190425 

From Danny: Is a rectangle a rhombus??? True or False Answered by Penny Nom. 





The area of a triangle 
20190425 

From troy: The base and the height of a right triangle are represented by the expressions below.
The area of the triangle is 28 square units. Find the lengths of the base and the height
of the triangle
base= x+4
height=x6 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. 





An equilateral triangle 
20190410 

From ethan: In equilateral triangle RST, R has coordinates (0, 0) and T has coordinates of (2a, 0). Find the coordinates of S in terms of a. Answered by Penny Nom. 





More on dominoes 
20190409 

From B: A previous answer
(http://mathcentral.uregina.ca/QQ/database/QQ.09.00/mark2.html)
considered a method to make a line of all 28 dominoes.
Since there are an even number of each value, such a solution can be put into a circle.
Aside from the choice of starting tile, is the solution unique? 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 don’t have that. An estimate would be all I need.
Thank you for you help.
Rob Answered by Harley Weston. 





The height of a building 
20190405 

From Hayley: A young man is 36 meters away from a building and looking at a bird sitting on top of the building. The man knows he is 85 meters away from the bird. How tall is the building? Answered by Penny Nom. 





4^x=2^x+6 
20190405 

From Olivia: How do you find the (b,n) if the solution of the equation 4^x=2^x+6 can be expressed at logb(n) where b and n are both prime numbers? Answered by Penny Nom. 





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. 





Percentage change in refractive error 
20190404 

From Ammara: Hi, I'm trying to figure out how a paper I'm looking at has found a percentage from the numbers below. its a paper comparing two lenses. it says that the new lenses 'slowed the progression of refractive error by approximately 50%'.
the refractive error with the old lenses was 2.26 after two years it was 3.28
the refractive error with the new lenses was 2.24 after two years the refractive error is  2.75
Thank you so much for your help it is most appreciated! Answered by Penny Nom. 





Internal acute angles 
20190402 

From karan: Prove that a convex polygon cannot have more than three acute internal
angles. Answered by Penny Nom. 





The volume of a pile of dirt 
20190401 

From Genevieve: We have a pile of dirt approximately 6 feet high by 15 feet wide by 80 feet long.
We need to know how many cubic yards of dirt are in this pile. Thank you Answered by Harley Weston. 





Percentages 
20190330 

From Mari: I am trying to find out what percentage of our worlds population does the youtuber
Pewdiepie have for subscribers? So he has 91 million subscribers and there are roughly
7.53 Billion people in the world. So what percent of our worlds population does Pewdiepie
have for subscribers? Am I asking this correctly? I am just curious for marketing reasons
and how much of the worlds market share does Pewdiepie have for his youtube
channel? I just do not know how to set up the problem to find the answer? Answered by Penny Nom. 





Three letter permutations 
20190326 

From liliana: I need to find a three letter permutation using four letters. I have no idea how to do this. Can you help me? Answered by Penny Nom. 





The volume of water in a pipe 
20190321 

From Abati: How can I calculate the volume of water in a pipe with below details;
Pipe diameter  6 inches
Length of pipe  127meters Answered by Penny Nom. 





A scale factor 
20190319 

From Miracle: A man in a photograph is 2cm tall. His actual height is 1.8m. Write a scale statement and determine the scale factor. Answered by Penny Nom. 





Slope and percentage 
20190319 

From Tom: I need a slope of 2 Inches every 30 feet what is the percentage to put on my pipe lazer. thank you Answered by Penny Nom. 





The area of a triangle 
20190319 

From Dylan: The area of a triangle is 108in squared. A base and corresponding height
are in the ratio 3:2. Find the length of the base and the corresponding
height Answered by Penny Nom. 





A dice game 
20190317 

From Remo: So, little game my kid came up with.
Dice are standard d6.
I roll a die, he rolls a die. If he gets the same number as me OR a bigger number he wins.
So far so good. Used the opportunity to get him to calculate the probabilities of him winning, see if I could get him interested into looking at this game from a more academic perspective. He did fine.
Then we upped the ante.
He rolls one die, I roll two dice. I his die has a number that is equal or greater than both of mine, he wins.
We had a bit of trouble solving that one, and had to resort to a table with all the results ( 6x36) to figure out where we stood.
Then again we upped.
He rolls two dice, I roll two dice.
If any one of his dice has a number equal to or greater than both of mine he wins. I only win if one of my dice is greater than both of his.
And we got stuck. Figured I would need to find a formula to resolve this one, as our earlier solution ( table everything ) suddenly is 36x36, giving well over a thousand possible results. And if we ever go bigger than that then we *really* are going to need another way to calculate it. Answered by Harley Weston. 





The bearing from C to A 
20190315 

From Emma: A is 6km due north of turbine B,
C is 4.5km due west of turbine B
Calculate the distance AC
Then calculate the bearing of C from A
Give your answer correct to the nearest degree Answered by Penny Nom. 





When is John's next birthday on a Friday? 
20190315 

From Darek: The question is the following:
Last Friday 4th of April of 2014 John was 40 years old. How old will John be the next time when his birthday fell on Friday?
Thanks for your help 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. 





A circle with a circular hole 
20190311 

From Sue: My little one is wondering if a circle with a circular hole could be described as an irregular semicircle.
As it has 2 sides but is not the standard shape. Could you share your thoughts ?? 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. 





A parabolic curve on a bridge 
20190309 

From monica: how do i fint the formula for my parabola with the provided information:
the golden gate bridge has a parabola
(343,160) = coordinate
(0,0)= vertex Answered by Penny Nom. 





A triangle of maximum area 
20190307 

From Tom: Triangle ABC is such that AB=3cm and AC=4cm.
What is the maximum possible area of triangle ABC? Answered by Penny Nom. 





Misuse of greater than 
20190307 

From Kenneth: I have an old business mathematics textbook. The authors have indicated that the following expressions indicate multiplication:
? is 2/3 greater than 90; ? is 2/3 smaller than 90. They also indicated that the following expression would indicate division: 30 is 2/3 greater than ? and 30 is 2/3 smaller than ?.
How can these phrases indicate multiplication and division? How can 60 be 2/3 greater than 90 and also smaller than 90 as indicated above. What were the authors thinking? I have added the page from the book that indicates what I have explained in my message
Kenneth Answered by Harley Weston. 





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. 





3 months loss and then a profit 
20190302 

From Ida: Let say, I have 10k of capital and I ran business for 4 months.
The first months i loss 50%, the second month i loss 50% and so do the third month.
The fourth month my profit is 50%
So can I calculate the balance of money that i have out of my capital? Answered by Penny Nom. 





Double the number of pennies each week 
20190228 

From Donald: If I save a penny a week,double it every week,How many weeks will it take to reach 1,000,000 dollars Answered by Penny Nom. 





The top half of a cone 
20190227 

From danica: What portion of the height from top that the cone be cut into two equal volume? Answered by Penny Nom. 





4 digit codes 
20190227 

From Sophia: How many 4 digit codes can you get out of a numbered key pad ? Answered by Penny Nom. 





A quadratic equation problem 
20190226 

From Em: One root of the equation
2x^2 + bx  24 = 0 is 8. What
are the possible values of b and
the other root? Answered by Penny Nom. 





f(x + 2) 
20190226 

From a student: How do you use f(x) = 3x+1 to determine the transformed function of f(x + 2)? Answered by Penny Nom. 





Weighing stars and hearts 
20190225 

From Zach: Two stars and one heart weigh 38 units. One star and one heart weigh 27 units what is the weight of each? 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. 





A word problem 
20190224 

From Briana: When 4 times the number increased by 30, the answer is the same as when 70 decreased by the number. What was my number? Answered by Harley Weston. 





Loan payment formula 
20190224 

From Kenneth:
I have a question regarding the loan payment formula shown below.
Calculating the Payment Amount per Period
The formula for calculating the payment amount is shown below.
Simple Amortization Calculation Formula
A = P X r(1 + r)n over (1 + r)n  1
where
A = payment Amount per period
P = initial Principal (loan amount)
r = interest rate per period
n = total number of payments or periods
Is this formula/calculation a condensed version of a longer calculation? I am curious to know how the (1 +r)n  1 was developed from the longer calculation. For example, r(1 + r)n may have been (r + rn)n. The n's are exponents.
I thank you for whatever helpful explanation that may be provided.
Kenneth Answered by Harley Weston. 





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. 





Adding and multiplying two numbers 
20190213 

From katie: what 2 numbers add to get 7 and multiply to get 2? 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. 





Factoring n^2+3n270 
20190211 

From Ashley: n^2+3n270 Answered by Penny Nom. 





A linear equation 
20190211 

From Nick: What's a linear equation? Answered by Penny Nom. 





5 numbers from 9 numbers 
20190211 

From John: How many combinations of 5 numbers be created with 9 numbers?
Sample: 1,4,7,9,12. Question the same with combination of 4 from 12?
Thanks, John Answered by Penny Nom. 





A cylindrical drum 
20190210 

From Ronald: I have a cylinder that is 32 inches round by 25 inches deep how much water can it hold Answered by Penny Nom. 





The exponential form of sqrt(13) 
20190210 

From isaebl: what is the exponential form of sqrt(13) Answered by Penny Nom. 





Function notation 
20190210 

From Paige: What is the difference between f(x+2) and f(x)+2? Answered by Penny Nom. 





Fractions with roots 
20190206 

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





An ice cream cone 
20190205 

From Eyuel: a scoop of ice cream has a 3inch radius how tall should the ice cream cone at the same radius be in order to contain all of the ice creams inside the cone Answered by Penny Nom. 





A 4 digit combination lock 
20190202 

From Brijanshu: I have a lock that contain only four no. 6,7,8 & 9 . How many possible password of four digit containing these Number. Answered by Penny Nom. 





A fraction of a cent 
20190201 

From michael: $ 300 divided by 1,000,000 is 00.0003 ... so, is that three hundredths of one ($ 00.0003) cent or what ... thanks 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. 





Macy's coin collection 
20190130 

From Sariah: Macy's coin collection has 2 pennies for every nickel. If she has 60 coins that are pennies or nickels, how many nickels does she have? Answered by Penny Nom. 





An equilateral triangle inscribed in a circle 
20190129 

From Penny: What is the length of each side of the largest equilateral triangle that fits inside a 3 inch diameter circle? Answered by Penny Nom. 





y=lnx+(1+ln2)/2 and y=x^2 
20190128 

From Mike: Prove that y=lnx+(1+ln2)/2 and y=x^2 touch each other.
The course is about logarithm and root functions... how should I solve this problem? Answered by Penny Nom. 





A scale factor 
20190127 

From Hannah: What is the scale factor of 36 meters and 1.5 centimeters? 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. 





The supplement of a complement 
20190125 

From Andrei: The value of the supplement of the complement of 8° is ?°. Answered by Penny Nom. 





What angle s its own supplement? 
20190125 

From Ciara: What is the angle of it's own supplement? Answered by Penny Nom. 





A median of a triangle 
20190124 

From Anna: For triangle J(1,4) K(3,1) L(3,4), find an equation for the median from vertex J 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. 





Numbering pages 
20190120 

From chungus: It takes 852 digits to number the pages of a book consecutively. How many pages are there? Answered by Penny Nom. 





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. 





Sale price and employee discount 
20190118 

From Margaret: What is the formula to find the
75% off full price item that was already marked 30% off? Answered by Penny Nom. 





A cylinder with a cone on top 
20190116 

From Berania: A water tower in New York City has the shape of a cylinder with a cone on top. The cylinder has a diameter of 12 feet and a height of 15 feet. The roof has an inclination angle of 25 degrees.
(a) Determine the height of the cone to the nearest tenth of a foot.
(b) Determine the overall volume of the tower to the nearest cubic foot. 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. 





Finance charge 
20190103 

From Kenneth:
Hello Math Central:
The calculation for determining the finance charge per $100.00 (FC/100) is determined by the following:
Finance Charge/Amount financed * $100.00 = the finance charge per $100.00
Since the denominator (amount financed) is not multiplied by $100.00, how does the result equal the finance charge per $100.00? The numerator (finance charge) is the only amount multiplied by $100.00.
Example 1. 3/4 * 6 = 18/4 not 18/24 The 4 is not multiplied by the 6.
Example 2. $49.00/$200.00 * $100.00 If $49.00 is divided by $200.00 the result is $0.245/$1.00. If $0.245/$1.00 * $100.00 = $24.50/$1.00. This answer is not $24.50/$100.00.
How does the above equal the finance charge per $100.00 when the denominator is not multiplied by $100.00?
If the division is not used to indicate the $0.245 per $1.00, the result becomes $49.00/$200.00 * $100.00 = $4,900.00/$200.00.
I thank you for any helpful reply.
..........
Kenneth
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. 





A rectangle problem 
20190101 

From ahamed: In rectangle ABCD, angle BCD is trisected. CE,CF meet the sides AB,AD at E,F. BE=6cm, AF=2cm so, find the area of the rectangle ABCD? Answered by Penny Nom. 





An octagonal deer blind 
20181231 

From Alan: My grandson and I would like to making a 6'x6' octagon floor for a deer
blind. He is eight yrs old and the math is outside my wheelhouse.
We need to know the length of the boards and angles of the corners please.
Thank you, Sincerely,
Alan Answered by Penny Nom. 





Two integers X and Y are selected at random 
20181231 

From Kenneth: Two integers X and Y are selected at random from the integers
1 to 8.If the same integer may be selected twice,find the probability
that;
1)XY=2
2)XY is 5 or more
3)X is greater than Y Answered by Penny Nom. 





y = f(x) 
20181230 

From yogita: What is the actual meaning of "f(x)" ? Please give me full explanation Answered by Penny Nom. 





Nonrepeating decimals 
20181228 

From Grace: What is non repeating decimal 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. 





The surface area of a dome 
20181218 

From Chithrabhanu: If a dom dia is 4.552 and the height is 1.21 what is the surface area? Answered by Penny Nom. 





cos(2x) = sin(x) 
20181218 

From Liz: Determine all values of x in [0,2pi] that solve the equation Cos(2x)=sinx 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. 





The height of a tower 
20181212 

From Pandey: Hello sir plz solve this question. If the shadow of a tower is found to be 10.5m longer when the sun's altitude is 45°AND60°. Find the height of the tower. Answered by Penny Nom. 





An open top box 
20181212 

From Kirklan: Jeremy wants to construct an open box from an18inch square piece of aluminum. He plans to cut equal squares, with sides of x inches, from each corner and then fold each side up to form the box. If Jeremy wants the volume of the box to be 432 cubic inches, what should the minimum length of the sides of the squares cut from each corner be? Find the volume, V, of the box as a function of x. Given: V = length × width × height. Answered by Penny Nom. 





The area and weight of sod 
20181211 

From Susan: I have equipment that will cut sod 30 inches across and 75 Feet in length?
how much will this be in square foot age ? Yards? Approximate weight? Answered by Penny Nom. 





Angular velocity 
20181205 

From Kolade: Krusty the Clown and Sideshow Bob have covered themselves in velcro, and shot themselves out of a large
cannon so that they stick to a huge rotating velcro wheel (don’t try this at home). As shown in Figure 1(a),
Krusty is now stuck to a point 3.00 m from the center of the wheel while Bob is stuck to another point 5.00 m
from the center. The wheel is rotating counterclockwise at 10.0 rpm. Conveniently a set of axes is suspended
just in front the wheel (Krusty asked for axes, like the ones you would use to chop wood, so that he and Bob
could chase each other with them in the usual wholesome entertainment he is known for. Unfortunately, the
set designer misunderstood.) The axes do not rotate with the wheel.
(a) Find Krusty’s and Bob’s angular velocities, in radians per second. Answered by Penny Nom. 





A puzzling equation 
20181204 

From Manny: Hello,
Can you explain why this is wrong:
1 = (1)^3 = (1)^{6/2} = ((1)^6)^{1/2} = (1)^{1/2} = 1 ??
Thank you Answered by Penny Nom. 





A square and a triangle 
20181203 

From Livvy: a square with a perimeter of 48 and a triangle with a perimeter of 38. when they are joined they make a pentagon. please find the perimeter
how can you find the perimeter of this. could you please help me? Answered by Penny Nom. 





The top of a truncated cone 
20181202 

From Sameer: Bottom cone radius 1124.height is 200. Top radius 15degree decree to bottom radius. Top radius how much ? Answered by Penny Nom. 





How many solutions does 3 (x + 4) = 3 x + 4 have? 
20181201 

From Milan: how many solutions does 3 (x + 4) = 3 x + 4 have? Answered by Penny Nom. 





Four digit numbers from 0, 1, 2 and 3 
20181130 

From A parent: how many four digit numbers can be formed using nos.0,1,2,3 if repetition is allowed? Answered by Penny Nom. 





y = x  1 
20181130 

From alexis: what does this mean y=x1 Answered by Penny Nom. 





Two cones formed from two circular sectors 
20181130 

From APARNA: The central angles of two sector of a circle are 60° and 120° . Using these sectors two cones are made. If the radius of the smaller cone is 5 cm, find the radius and base area of the larger cone. Answered by Penny Nom. 





0.025% of 575 billion 
20181128 

From JoAnne: What is .025% of 575 billion dollars? Answered by Penny Nom. 





Ordering fractions 
20181125 

From Mae: order these from least to greatest:
19/6, 3 5/14, 83/21 Answered by Penny Nom. 





1 acre by 3 inches deep 
20181123 

From Cheri: How many yards of soil does it take to cover 1 acre in 3 inches of soil? 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. 





Terry was twothirds as old as Nia 
20181119 

From Makenzy: four years ago, terry was twothirds as old as nia. now terry is threefourths as old as nia. how old is each now Answered by Penny Nom. 





What was the original number? 
20181118 

From jaydaleigh: Mark was thinking of a number. Mark adds 11 to it, then doubles it and gets an answer of 40.5. What was the original number? Answered by Penny Nom. 





Percentage markup 
20181117 

From Sher: Cost price is $32,500 and selling price was $ 85,495.25, what percent markup was made? Answered by Penny Nom. 





2/5 as much time 
20181116 

From Izzy: If Patricia spent 3/8 of her time cleaning her room. She spent 2/5 as much time
washing the dishes as she did cleaning her room. What fraction of time did Patricia
spend Washing dishes? And it wants us to simplify our answer Answered by Penny Nom. 





4 + 3/2 
20181115 

From Chloe: so I have this paper and I'm confused, 4 + 3/2=???? so I originally got 1/2 but I looked
at Calculator papa and he says 5/2 and then I looked at google and all I got was 2.5 and i
am so confused and lost. Answered by Penny Nom. 





Price before VAT and a discount 
20181115 

From Carol: I bought a computer for £330.
The selling price included VAT at 20%.
Then I was allowed a staff discount of £30.
What was it’s original price before the VAT and staff discount? Answered by Penny Nom. 





The original cost when you only know a percentage 
20181113 

From john: I was wonder how to find the Original cost when you don't know original cost
The amount paid was 13.82 that is suppose to represent 20%
because Insurance pays 80%
Thank You Answered by Penny Nom. 





A line cuts a curve 
20181111 

From roxanne: Hello, i need to ask a question, do you mind explaining and writing the formula of how to solve equations such as "find the set values of k for which the line y2x5 cuts the curve y=x^2 +kx+11" please Answered by Penny Nom. 





The price of eggs rises 10 cents per dozen 
20181110 

From Maddie: Hi! I'm currently struggling with a word problem that says:
"If the price of eggs rises 10 cents per dozen, one will be able to get 2 dozen fewer eggs with $6.00 than was possible at the lower price. What is the lower price?
We are working on completing the square and all of the problems I've done so far in this chapter require using that method. If possible and needed, could you explain how to set up the equation?
Thank you so much! I appreciate all your help!! Answered by Penny Nom. 





Speed 
20181106 

From Dolores: if I drove 3/4 mile in 32 seconds, what was my speed ? 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. 





Why 1/2 in the area of a circular sector? 
20181026 

From Ariel: In the equation for area of a sector=1/2r^2theta why is it 1/2? Please explain conceptually not algebraically. Answered by Penny Nom. 





Why 1/3 in the volume of a cone? 
20181020 

From Keith: In the formula for the volume of a pyramid, Volume = 1/3 * base * height, where does the 1/3 come from, intuitively? Answered by Penny Nom. 





f(x) and f(x) 
20181019 

From Simran: what is difference between f(x) compared to f(x) on graph Answered by Penny Nom. 





Angular speed 
20181018 

From Akidima: A bicycle wheel rotates uniformly through 2.0 revolutions in 4.0 seconds .
What is the average angular speed of the wheel Answered by Penny Nom. 





Filling a candy box 
20181016 

From Stephanie: My child had the question: A candy box has the following measurements.
10x6x4Find the total volume. (We got that one right 240in3)
But... then it said “How many 1/2 inch cubed pieces of candy can fit in the box?
This is where we disagree. Please help. Answered by Penny Nom. 





Covering 6 acres with dirt 
20180927 

From Scott: How many cubic yards of dirt would come from 6 acres, 6 ft. deep? 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. 





Two curves 
20180923 

From Megan: How do i find the interception points of xy=2 and y=x+3? Many thanks! Answered by Penny Nom. 





The pointslope equation for a line 
20180923 

From Sally: The equation of the line in pointslope form for the line passing through the point ( 4, 6) and parallel to the line y = 6x + 2. Describe the steps. Answered by Penny Nom. 





An inequality with no solution 
20180920 

From Alena: I'm trying to help with a homework problem. Can you please help me?
2kx  3k < 2x + 4 +3kx
We are solving for "k" with no solution. Answered by Penny Nom. 





Compatible numbers 
20180919 

From Jessica: Hello, I'm having trouble helping my daughter she is in 5th grade and I tell you her math is so much different then the math I learned in school and I been out of school for quite some time so it's a little hard for me.
Anyway her math is very confusing for me they are saying use compatible numbers to find two estimates.
I have no idea what that even mean I tried using Google but still don't get it .
The problem is 12 divided by 478 using compatible numbers to find two estimates.... please help Answered by Penny Nom. 





The sum and difference of two numbers 
20180917 

From Feni: The sum of two numbers is 4. The difference of the two numbers is 2. What are the two numbers? Answered by Penny Nom. 





A gas and oil mixture 
20180916 

From April: For a new motor bike, the recommended ratio of gas to oil is 27:1 by volume. How much gas and how much oil are needed to fill a 14 L tank on a new motor bike?
Thank you Answered by Penny Nom. 





Predicting the number of fish in a lake 
20180916 

From April: A researcher catches 30 fish in a pond, attaches a marker to their fin and releases them. The next day she places a large net in the water and catches 9 fish. 3 have the marker attached to their fin. Can she predict the number of fish in the pond???
Thank you Answered by Penny Nom. 





The volume of a hotel soup pan 
20180915 

From Melanie: If the hotel pan measures 12 inches long x 5 inches wide x 6 inches tall, how many quarts of soup will the hotel pan hold? Answered by Penny Nom. 





Velocity 
20180914 

From Adrian: If Jill was traveling at 300 miles in 4 hours due South what was his velocity in miles per second. Answered by Penny Nom. 





Covering a region with black Mexican Rock 
20180914 

From Lenton: I have a 48 sq. feet area that I need to cover.
How many cubic ft would I need to cover 48 sq. ft.? Answered by Penny Nom. 





Exponential form 
20180914 

From Saquanna: What is 25 in exponential form 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. 





Fixed cost 
20180913 

From Heather: On the bus question you answered, what would be the fixed rate? Is that the rate per person or is that also the base rate? ( cost of empty bus)? Answered by Penny Nom. 





Exponential form 
20180912 

From Grace: hi, I can't figure out how to do 735 in exponential form. note that im only in 5th grade and its not supposed to be in the scientific notation or whatever. okay, thanks! Answered by Penny Nom. 





A locus of points 
20180903 

From Ericka: Find the locus of points three times as far from (0,4) as from (2,0) Answered by Penny Nom. 





Golf schedule for 12 players over 8 days 
20180903 

From William: We have a golf trip with 12 golfers
we are playing 8 rounds together......we want to mix the group up at best possible w/o too much overlap.......
thoughts? the math is way over my head...
even if we play the first 6 rounds with different partners, then the last 2 can be repeats ...or whatever the math works out 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. 





The sum and difference of two numbers 
20180830 

From Saranya: Hi,
The question is to find the numbers from sum and difference.
The Sum = 14 and the difference = 2
I found in this web site some useful answers. but my kid is going second grade only. She don't know how to do a division or multiplication.
So can you please explain on how to find the answer using only the Addition and Subtraction.
Thanks in advance. Answered by Penny Nom. 





Working with percentages 
20180826 

From Kenneth: 16 is 4% of what amount?
The answer can be determined by the following unusual manner:
4% = 16
1% = 4
100% = 400
Can the following solutions for the following be determined by using the
same type of calculation?
16 is ?% of 400
? is 4% of 400
I thank you for your reply. Answered by Penny Nom. 





Robbie and fran run laps 
20180826 

From khansa: robbie runs 3 laps for unknown number of days. fran runs 3 times as many laps each day for unknown number of day. what is the formula for their combined total number of laps Answered by Penny Nom. 





A rotating wheel 
20180824 

From Kay: A wheel with a radius of 7 inches is rotating at 4 revolutions per second. What is the
linear speed v, in feet per second? Answered by p. 





Two intersecting tubes 
20180815 

From Tommy: Hi, I am trying to determine a mathematical model for two metal tubes joining at various degrees for weld.
For instance, if I am trying to join the end of a tube to the side of another at a 90 degree angle, it will be a simple profile cut out of the joining tube.
Where it gets tricky is if you want to join the new tube at a given angle.
It would be very helpful if you could give insight as to how I can solve this problem or an equation I could work off of.
Thanks for the help!! Answered by Edward Doolittle. 





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. 





A cube in a cylinder 
20180813 

From Geli: A cylinder with a radius r and height 2r+4 contains a cube with edge length r√2. What fraction of cylinder volume is taken up by the cube Answered by Penny Nom. 





Amy and Joey on a circular track 
20180813 

From Zoe: Amy and Joey are situated on a circular track 400 feet around.
Joey starts running at a rate of 10 feet per second.
Amy waits for a full minute, then starts running from the same point (in the same direction) at 12 feet per second.
How many seconds elapse before Amy passes Joey on the track? Answered by Penny Nom. 





Exponents 
20180813 

From Ella: What is the radical form of 3xy raised to 5 quantity three fifths? Answered by Penny Nom. 





Form a cone from a circle sector 
20180812 

From Tinashe: A 216 sector of a circle of radius 5cm is bent to form a cone. Find the radius of the base of the cone and its vertical angle. Answered by Penny Nom. 





5 mm of water over 1 hectare 
20180810 

From Joyce: Please help me with this question.
How many tonnes of water fell on 1 hectare of land during a rainfall of 5mm? Answered by Penny Nom. 





Truncated cones 
20180808 

From Belgacem: Hello, I have a truncated cone: height 500mm , Base radius=147mm and I want to calculate the Top surface radius. How to do that? thank you Answered by Penny Nom. 





Paving stones area 
20180808 

From Declan: I am thinking of buying some reclaimed block paving stones. There are 750 pieces in total.
60% are L 140mm x W 140mm x H50mm
40% are L170mm x W140mm x H50mm
How much area will this cover? Answered by Penny Nom. 





The record for a soccer team 
20180720 

From Payal: A soccer team plays six games in one month. Each game results in a win, loss, or tie.
For this soccer team, how many different sets of results are possible for the six games? Answered by Penny Nom. 





How many students passed the test? 
20180720 

From florian: In Mr. Edgecomb's math class, 30 students took an exam on statistics. If the average passing grade was 84, the average failing grade was 60, and the overall average was 80, how many students passed the test? 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. 





A sulphuric acid solution 
20180712 

From Tan: How much 96% h2so4 to add into sulphuric acid 30% in order to make it to 50% sulphuric acid? Answered by Penny Nom. 





A circle inscribed in a regular polygon 
20180712 

From Naveen: The radius of inscribed circle for n sided regular polygon of a side a is?
Please with proof Answered by Penny Nom. 





The price of a watermelon 
20180707 

From errin: the price of the watermelon is directly proportional to its weight. If a watermelon that weighs 22 pounds cost $5.40, how much will a 17.5 pound watermelon cost? Answered by Penny Nom. 





Four odd factors 
20180704 

From Manchali: Find a number that has 4 factors and all of them are odd numbers. Answered by Penny Nom. 





The surface area of a levee 
20180704 

From John: Figuring out the surface area in sq. Ft. Of a levee
Height:10’
Top of levee width: 6’
Width of base (from toe to toe): 40’
Length of levee: 1,250’ Answered by Penny Nom. 





Creating a number sentence 
20180629 

From trish: First I have to solve the problem. Then write a number sentence for the problem.
The problem: By installing a $120.00 thermostat that reduces the temperature setting at night a family hopes to cut its annual fuel bill for heating oil by 8%, and recover the cost of the thermostat in fuel savings after 2years. What was the family's annual fuel bill before installing the thermostat?
Thanks can't figure this one out! Answered by Penny Nom. 





Soil in a raised bed 
20180624 

From Georgia: Good Afternoon,
I'm planning on building a raised bed garden measuring
6 feet long x 4 feet wide x 12 inches deep.
I'm not sure how to calculate the amount of soil to fill it up. I will have to
purchase the soil in 2 cubic feet bags.
I've read several articles about this topic on various gardening websites,
and one of them stated it would take a ton of soil to fill up an 8 foot long x
4 foot wide x 12 inch deep raised bed garden.
I'd greatly appreciate it if you could help me out with this quandary.
Thank you for your prompt and courteous response.
Kind Regards,
Georgia Answered by Penny Nom. 





Three consecutive whole numbers 
20180622 

From whaha: the sum of three consecutive whole numbers divided by 4 is equal to 6. find the numbers. Answered by Penny Nom. 





The product of two numbers 
20180619 

From amie: the product of two numbers is 108.when the larger number is divided by the smaller number the quotient is 3. What are the number.tnx 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. 





A question about the empty set 
20180617 

From Andrey: Hello there!
I got that an empty set is a subset of every set.
There is a question.
Is an empty set an element of every set?
∅ ⊆ {x}True
∅ ∈{x}?
Sorry if the question is easy. A set theory is a bit confusing. Answered by Penny Nom. 





The number of terms in an arithmetic sequence 
20180615 

From Don: how many terms in arithmetic sequence are there if the first term and the last term are 3&59 respectively in common difference is 4? Answered by Harley Weston. 





The base for a circular pool 
20180610 

From Adam: How many sheet of 4ft by 8ft foam would I need to lay under a pool 15dt in diameter Answered by Penny Nom. 





A tangent to a circle 
20180610 

From Bellle: Determine the equation of the circle which has its center at (3,1) and tangent 3x4y+5=0 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. 





Are those two equations the same? 
20180605 

From Francisco: Solve for y: 2(x+3)=y x=5
Solve for y: (x+3)2=y x=5
Are those two equations the same? Answered by Penny Nom. 





The difference between two numbers is 3 
20180605 

From Hannah: write a pair if integers whose difference is 3 ( given that the greater number is 8 ) Answered by Penny Nom. 





The volume of a berm 
20180604 

From Mike: Have a berm that is 700’ long, 29’ y’all and needs a 20’ top with 51 slope on one side and 31 slope in the other Answered by Penny Nom. 





Two odd integers 
20180604 

From Pleroma: The product of two alternate odd integers exceeds three times the smaller number by 12.
What is the larger number? Answered by Penny Nom. 





$96 is 66 2/3% of what dollar amount? 
20180531 

From mary: $96 is 66 2/3% of what dollar amount? Answered by Penny Nom. 





Taking 6 pills 
20180529 

From Dave: My motives are simple, I want to get revenge on my brother who, unbeknown to me,
repeatedly cheated when we played online Scrabble! Can you help?  he has posed this
question knowing that I'll struggle to get the solution.
Question: He is taking 6 pills a day, if he takes the pills in a different order each day,
how long will it be before he takes the pills in the same order on the same date again?
I think leap years might come in to it!
Will I confess to using you guys?  I'll think about that one. 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. 





An equation with rational coefficients 
20180526 

From Anagh: If x and y are rational number and
(x+y) + (x  2y)√2 = 2x y + (xy1) √5
Then find the value of x and y. Answered by Penny Nom. 





Converting inches to centimeters 
20180525 

From Jason: Hi!
Is there a method to approximately convert inches to cm in my head without using a calculator?
Thanks!
Jason Answered by Penny Nom. 





Pre tax and post tax percentages 
20180522 

From Tom: Hi,
I work in a clothes shop which can also do mailorders. My Head Office
has sent a report with which we can check the records we keep in store
tally with those at HO.
According to that report we have taken £2578.25 in orders, excluding VAT (20%),
which would therefore be £3093.91 including VAT (2578.25+20%=3093.91).
According to my records, we have taken £3179.32 including VAT, which would be
£2543.45 excluding VAT (3179.3220%=2543.45).
Why is it that the difference between the VAT inclusive figures (3179.323093.91) is +£85.41, but
the difference between the VAT exclusive figures (2543.452578.26) is £34.81?
Now, I can see from the report that 1 order has not been recorded by HO, and I
know that our average order value is around £30, so the £34.81 makes sense.
But surely both figures should be a minus, regardless of whether they include VAT?
I'm sure there is an obvious answer, but I just cannot see it! Any help would be gratefully
received.
Thanks,
Tom Answered by Penny Nom. 





The area, radius and slant height of a cone 
20180518 

From joette: If you have a cone how to find the slant height when given the area and radius? 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. 





Write these fractions from greatest to the least 
20180518 

From angela: math fraction greater to the least
1\5 ,1\2 or 1\4 Answered by Penny Nom. 





4 digit "combinations" 
20180518 

From Marvin: I am designing a game, and I need away of figuring this out without having to write numerically all these numbers
4 digit combinations 0 through 13 nonrepeating 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. 





Subdividing a rectangle into squares 
20180513 

From jeverzyck: A rectangular board is 108cm wide and 156 cm long Equal squares as large as possible
are ruled off this board.Find the size of the square.How many squares are there? Answered by Penny Nom. 





Rods,poles and perches 
20180513 

From roy: i have some land and its measured in rods poles and perches
how cann i convert to understand it more 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. 





An egg falls from rest 
20180510 

From Amy: An egg falls from rest a distance of 75cm to the floor.
Neglecting air resistance, at what speed does it hit the floor? Answered by Penny Nom. 





An unknown number 
20180510 

From David: Sam chose the number 35 and made up these clues."my number is odd. It is a multiple of 5. It's other factor is greater than 5. My number is less than 40. What is my number and what is it's other factor? Are Sam's clues correct? Answered by Penny Nom. 





The square root 3 in exponential form 
20180509 

From Paige: how do you write the square root 3 in exponential form Answered by Penny Nom. 





Converting decimals to common fractions 
20180508 

From Ruth: what does the 0 represent in .018 versus the decimal .180? As in, changing these to fractions? Thank you. Answered by Penny Nom. 





The volume o a hemisphere 
20180506 

From Sambox: When I have a hemisphere with a volume of 700Pi m^3 what is the radius? Answered by Penny Nom. 





Soccer fans and cricket fans 
20180506 

From Chibo: In a survey of 60 sport fans, 45 enjoy soccer, 35 enjoy cricket and 10 do not enjoy either soccer or cricket, but some other sports.What percentage of sports fans enjoys both soccer and cricket? Answered by Penny Nom. 





A fraction 
20180502 

From Adwin: The denominator of a rational number is greater than its numerator by 8. If the numerator is increased by 17 the number obtained is 3 by 2. Find the number. Answered by Penny Nom. 





Gauss' Addition of whole numbers. 
20180430 

From Brad: I found this on your site. Question: what is the sum of the first 100 whole numbers??
Is there a different formula if the numbers begin at a number other than one? For example
What is the series I want to add is goes from 7  53? Answered by Harley Weston. 





Spreading soil over 10 acres 
20180429 

From Joe: If you have 54000 cubic yards of soil and want to spread it over 10 acres of land, by how many inches would the ground level rise? Answered by Penny Nom. 





The weight of a cylinder 
20180427 

From Jared: What is the formula for the weight of a cylinder (not hollow) made of cast iron if it has a height of 5.25 inches and a diameter of 1.75 inches? Answered by Penny Nom. 





Throwing a football 
20180426 

From Abby: Daring Danny's threw a football at an angle of 40 degrees to the horizontal. The football hit the ground at 36 feet. Danny is 5 feet 1 inch tall. Find the initial velocity
I have been trying to figure this problem out for forever! Please help! I am really confused because I don't know time either and you are supposed to find that as well as velocity. Answered by Penny Nom. 





A rectangular prism with rounded corners 
20180425 

From Jackie: Rectangular prism that is 40 by 20 with rounded corners with a radius of 2.5.
What would the surface area be? 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. 





Seven tangent circles 
20180423 

From Domenick: How to calculate the circumscribed and inscribed circles formed by seven .019685 diameter circles arranged in a circle with all seven circles tangent to each other? Answered by Penny Nom. 





A volume expression for a pyramid 
20180423 

From Shaheer: Do a three sided pyramid and a square pyramid have the same formula if you want to calculate the volume? Answered by Penny Nom. 





The distance between two men 
20180421 

From Kristin: If a 5 ft 6 in man gets hit at a downward 45 degree angle by a 5 ft 10 in man, how far apart are the two men? AND, would the shorter man have to be kneeling or standing? Is there a formula and answer for this question? Answered by Penny Nom. 





Nickels, dimes, and quarters 
20180420 

From Patti: A copy machine accepts nickels, dimes, and quarters. After 1 hour, there are 30 coins total, and their value is $5.10. How many nickels, quarters, and dimes are in the machine? (Hint: There are exactly five different solutions.) Answered by Penny Nom. 





How to find the area of triangle? 
20180419 

From g.a: how to find the area of triangle Answered by Penny Nom. 





A cone formed from a circular sector 
20180418 

From Jessica: A circle has a radius of 7.5cm. A sector with an angle of 240 degrees is cut out from the sector. If the sector is folded to form a cone. Find the length of the cone. Answered by Penny Nom. 





Pool Digit Combinations 
20180418 

From Jacob: I need to know all the possible 3 digit combinations from the following pool of digits: 1st pool (1,2,3), 2nd pool (4,5) and the 3rd pool (7,8,9,0). Each pool has to be represented in the combinations.
The numbers can be repeated as long as they are not of the same set.
Example for not repeating: 123 is ok but not 321 or 231,132,213, etc.
The question is somehow related to Mike's but the difference is the digits are allocated into pools. Your help can assist me solve a mystery. Thanks. Answered by Penny Nom. 





A circle inscribed in a quarter circle 
20180416 

From abhijeet: ABC is a quarter circle and a smaller circle is inscribed in it. if AB = 1cm then find the radius of smaller circle Answered by Penny Nom. 





A triangle in a cube 
20180416 

From Sohel: A cube has an edge of 4 cm. A triangle is formed by joining the middle point of one face of the cube to the ends of a diagonal of the opposite face . What will be the area of the triangle ? Answered by Penny Nom. 





What is small fourdigit whole number? 
20180415 

From Rajesh: What is small fourdigit whole number? Answered by Penny Nom. 





The angles of a trapezoid 
20180414 

From Gautham: In trapezoid ABCD, sides AB and CD are parallel, \angle A = 2angle D, and angle C = 3angle B. Find angle A. Answered by Penny Nom. 





The mass of a durian 
20180414 

From REEVASSHINIE: A watermelon with a mass of 5 kg and two durians with the same
mass are placed on an electronic balance.If the reading shown on the
balance is m kg,write an expression for the mass of a durian Answered by Penny Nom. 





The length of a diagonal of a box 
20180413 

From Valentina: A packaging box for a metal rod is 7.5 inches along a diagonal of the base the height of the box is 18 inches what is the lengh of a diagonal of the box? Answered by Penny Nom. 





Covering a region with mulch 
20180413 

From Roberta: I have a fall zone area of approx. 700 sq ft. that I have to cover with a 6in depth of mulch. How much mulch would I need to purchase? Answered by Penny Nom. 





Division and remainders 
20180412 

From Yogendra: A number is divided by 5,7 and 9. Reminder are 1,2 and 3 respectively.
What is the number?. Give suitable calculations. Answered by Penny Nom. 





Graham's money box 
20180412 

From Tasnim: Graham's money box consists of sh.10 and sh.5 coins. There are 24 coins and it's total value is 150. Find how many of each coins are there in the box Answered by Penny Nom. 





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. 





Rolling 2 dice 
20180406 

From Jose: Find the probability p that the sum is as stated when a pair of dice is rolled.
(a) Even and doubles.
p=
(b) Even or doubles.
p= 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. 





Factoring a quadratic 
20180402 

From Billy: I need help factoring the following question:
4x(squared) 10x +16. Answered by Penny Nom. 





The price of a sheet of metal 
20180402 

From Nydia: What is the formula to calculate the following:
I nee to find out what the sheet price be. The dimensions are 2000x3000 mm into ft they are 78x1181.
The sqft price I have is $22.16. How do I figure out the sheet price from that? Answered by Penny Nom. 





A circle problem 
20180330 

From ahamed: the diameters of a circle AB and CD intersect each other at O perpendicularly. Then a chord DF is drawn. AB and DF intersect at E. DE=6cn and EF=2cm.find the area of thw circle Answered by Penny Nom. 





The volume of a tent with a hexagonal base 
20180327 

From shohel: A tent has its base in the shape of a regular hexagon whose sides are 10m . If the height of the tent is 12m , then find its volume. 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. 





The mean and median 
20180324 

From Myrte: Is the median always smaller then the mean? Answered by Penny Nom. 





Distance between a chord and its arc on a circle 
20180323 

From Doug: Specifically, what is the subject distance for the Earth orbiting for 27 days. Assume the orbit of the Earth to be a circle have a 93 million mile radius. Assume the angle of arc to be (27/365) x 360 degrees. Thank you. Answered by Penny Nom. 





A circle and two chords 
20180321 

From Ella: In a circle, a 30 unit chord is 5 units closer to the center than a 20 unit chord. Find the radius. Answered by Penny Nom. 





Interest for 3 years 
20180321 

From Mary: How much interest do you pay if the charges 0.12% over 3 years loan $4999 Answered by Penny Nom. 





Walking a fraction of a mile 
20180320 

From Jamie: Who walked a fraction of a mile that is closer to neither 0 nor 1 ? Explain
Avery 1/6
me.Nunez 5/6
Ms. Chang 1/3
Mr. O’Leary 4/8
Miss Lee 4/6 Answered by penny Nom. 





Two regular pentagons 
20180319 

From Kip: The ratio of the corresponding apothems of two similar regular pentagons is 5:7 What is the ratio of their areas? Answered by Penny Nom. 





A circle of circumference 4*pi*r 
20180319 

From Ankith: If the circumference of a circle is 4*pi*r, what is its area?
i) 4*pi*r^2
ii) 2*pi*r^2
iii)3*pi*r^2
iv) pi*r^2 Answered by Penny Nom. 





A penny is thrown from the top of a building 
20180316 

From Zoraida: A penny is thrown from the top of a 26.7meter building and hits the ground 3.39 seconds after it was thrown. The penny reached its maximum height above the ground 0.89 seconds after it was thrown.
a. Define a quadratic function, h, that expresses the height of the penny above the ground (measured in meters) as a function of the number of seconds elapsed since the penny was thrown, t.
b. What is the maximum height of the penny above the ground? Answered by Penny Nom. 





1/4 acre of land 
20180315 

From Jean: I have 1/4 acre of land.it is square.what should the measurement be for each side be in feet Answered by Penny Nom. 





Solve when the variable is in the exponent 
20180315 

From Dan: 50 x 2^n = 1,000,000
2^n = 20,000
what does n equal? Answered by Penny Nom. 





The volume of a cube 
20180315 

From Eli: An outdoor art display is a metal cube with edge length 39 feet. What is the volume of the cube in cubic feet? In cubic yards Answered by Penny Nom. 





An equilateral triangle inscribed in a circle 
20180315 

From Olatundun: An Equilateral Triangle Of Side 20cm Is Inscribed In A Circle.Calculate The Distance Of A Side Of The Triangle From the Centre Of The Circle. Answered by Penny Nom. 





A rope fom a dock to a boat 
20180314 

From Tracey: A boat is tied with a rope to a dock that is 16 feet tall. Along, the water, the water the boat is 17 feet from the dock. How long is the rope connecting the boat to the dock? Let c represent the length of the rope.? Answered by Penny Nom. 





Which movie lasts longer? 
20180314 

From YKJAJA: Which movie lasts longer than the other?
A) “space adventure” lasts for 1 2/3 hour
B) “animal world” lasts for 15/12 hour Answered by Penny Nom. 





A geometric series 
20180313 

From nathi: 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.
The maximum height part is not answered. Answered by Penny Nom. 





Solve sinX=0.703X for X 
20180313 

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





The sum and difference of two numbers 
20180313 

From samima: Two numbers have a difference of 0.85 and the sum 1.What are the numbers? 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. 





Graphing y = 2x  1 
20180312 

From Himanshu: Hi I Himanshu I having 1 doubt on 1 question this question of graph how to draw y=2x1 Answered by Penny Nom. 





The intersection of a curve and a line 
20180308 

From lola: find the set of values of constant C for which the line y=x+c intersects the curve y=2 square root x at, at two distinct points 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. 





Some 5 number sets 
20180302 

From Sarah: Hello! My question is:
If I have 5 columns of numbers, and I want to create all possible combinations
(or is it permutations?) How can I do that? For example all numbers in each
column may not appear in any other column. so:
column 1: 1,2,3,4,5
column 2: 6,7,8,9,10
column 3: 11,12,13,14,15
column 4: 16,17,18,19,20
column 5: 21,22,23,24,25
how may I determine all the possible ways I can get sets of 5 out if this? Thanks! Answered by Penny Nom. 





Expand (5x9)(5x+9) 
20180301 

From adil: expand the following:
(5x9)(5x+9) Answered by Penny Nom. 





Aspect ratio 
20180301 

From brad: can you help me find the width if I know the length and aspect ratio of a object?
length = 78
aspect ratio = 1.42
width=?
length = 107
aspect radio= 2.02
width= ?
thank you Answered by Penny Nom. 





An item on sale costs 55% of the original price. 
20180228 

From Debra: An item on sale costs
55%
of the original price. The original price was
$51
. Answered by Penny Nom. 





Parents, grandparents, great grandparents, ... 
20180228 

From jessica: every person has 2 birth parents, 4 birth grandparents, and so on. These people are known as ancestors. How many ancestors does a person have in each generation? write in exponential form. 3ed generation, greatgrandparents? 4th generation? 10th generation? Answered by Penny Nom. 





Is a rectangle a parallelogram? 
20180228 

From ellie: is a rectangle a parallelogram? Answered by Penny Nom. 





The limit of (e^x1)^(1/x) as x tends to 0 
20180227 

From ARGHA: Find the limit of (e^x1)^(1/x) as x tends to 0. Answered by Penny Nom. 





A cyclist reduces his speed 
20180227 

From Katherine: Suppose the winner had reduced his average cycling rate by .1 mile per hour.
By how much would his time have changed?
(the cyclist's rate is 23.66 miles per hour and the answer to the question before this
one was that he cycled 2,292 miles in 96.87 hours) Answered by Penny Nom. 





A four digit pass code 
20180226 

From Jessica: I was trying to fond out how many combinations could there be for a four digit pass code to a phone when no numbers are repeated? Answered by Penny Nom. 





Billions and trillions 
20180225 

From Sheila: How many 50 billion equal 100 Trillion ?
How many 20 billion equal 100 Trillion?
How many 500 million equal 100 Trillion?
How many 50 million equal 100 Trillion?
How many 50 thousand equal 100 Trillion? Answered by Penny Nom. 





$525 is shared among three friends 
20180225 

From Iyanla: If $525 is shared among three friends: Paul Katherine and Brandon so that Paul gets $15 less than Brandon and Katherine gets 4 times as much as Paul, how would I solve this equation? Answered by Penny Nom. 





The perimeter of a square 
20180225 

From Alicia: What's the perimeter of a square with 441cm square Answered by Penny Nom. 





Multiplies and factors 
20180224 

From Lil: Is a multiple the same as a factor? Answered by Penny Nom. 





Dividing a region in half 
20180224 

From mandy: There is a line through the origin that divides the region bounded by the parabola y=4x−5x2y=4x−5x2 and the xaxis into two regions with equal area. What is the slope of that line? Answered by Penny Nom. 





The slope of a line 
20180222 

From Steve: my current slope is 6%. I want to know how many inches higher I will be at 18'
Thanks Answered by Penny Nom. 





2.5 gallons of liquid, one half an inch deep 
20180221 

From Cain: How many square feet would 2.5 gallons of liquid cover at half an inch deep? 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. 





2 (a + 4) = 18 
20180218 

From rebecca: 2 (a + 4) = 18
how do i do this with showing it distributive property ( symbolically)
Thank you! 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. 





What is the speed of the skateboarder? 
20180213 

From Zack: It takes a skateboarder 20 minutes to get to school, which is 6 km from home. What is the speed of the skateboarder? Answered by Penny Nom. 





Solar cells 
20180212 

From karla: Solar (photovoltaic) cells convert sunlight directly into electricity. If solar cells were 100% efficient, they would generate about 1000 watts of power per square meter of surface area when exposed to direct sunlight. With lower efficiency, they generate proportionally less power. For example, 10% efficient cells generate 100 watts of power in direct sunlight. Suppose you want to supply 22 kilowattss of power to a house by putting solar panels on its roof. For solar cells with the average power of 49 watts per square meter of solar panels, how many square meters of solar panels would you need? Assume you can make use of the average power from the solar cells 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. 





Water in a cone 
20180210 

From Shuvo: The diagram shows a vertical crosssection of a container in the form
of an inverted cone of height 60 cm and base radius 20 cm. The circular
base is held horizontal and uppermost. Water is pursed into the
container at a constant rate of 40 cm3/s.
Show that, when the depth of water in the container is x cm, the
volume of the water in the container is (πx^3)/27 cm3.
Find the rate of increase of "x" at the instant when "x" = 2. Answered by Penny Nom. 





3 yards 6 inches times 7 
20180208 

From Tamara: 3 yards 6 inches × 7 Answered by Penny Nom. 





A parallelogram, a rhombus and a rectangle 
20180207 

From Sambo: what do parallelogram, rhombus and rectangle have in common? Answered by Penny Nom. 





The wholesale price given the retail price and the markup 
20180207 

From Matthew: Retail $99
Markup is 80%
What is the equation to find the original (wholesale) price (55)?
thanks Answered by Penny Nom. 





Adding two negatives 
20180204 

From Pinasshakoane: (23)+(3) Answered by Penny Nom. 





A question about perfect squares 
20180204 

From Jolyn: Find the smallest possible value of a whole number m if 648x m is a perfect square Answered by Penny Nom. 





The code on a new phone 
20180202 

From Maria: Hi 
My husband gave me a new Samsung Galaxy mobile for out anniversaire gift. He set me a challenge which I have to solve before I can use the Phone. He has set the pin code with numbers 4, 7 and 0 and created a four digit code with the said numbers. Is there a way I can somehow list all possible combinations and try them all? Thanks! 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. 





Pricing a piece of plate steel 
20180129 

From Simo: I have a piece of plate that is 2500mm x 8000mm x 20mm thick and costs $7693.00
what is the formula to work out what 1000mm x 1000mm is worth? 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. 





The sum and difference of two numbers 
20180125 

From Ali:
Hello,
I was looking at the original question that was posted and answered by
your team:
http://mathcentral.uregina.ca/QQ/database/QQ.09.07/s/donna1.html
I used the 7 and 4 as example and not looking for 39 per original
question:
A=7
B=4
7+ 4 =11 and 74 = 3
We end up with 11 +3 = 14
A= 14/2 give use 7
B = how do you solve for B or 4 with out knowing anything about 3 or any other numbers ?
Thank you
Ali Answered by Penny Nom. 





The equation of a line 
20180123 

From Gloria: Write the equation of a line in standard form through the point (1, 6) and perpendicular to the line 2x –y = 9. 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. 





Profit margin and markup 
20180118 

From Oyewumi: Mr A sold a car to Mr B at 20% profit margin and Mr B sold the car to Mr C at 30% markup on cost. If Mr C got the car at $x.
1. How much did Mr A buy the car in terms of x.
2. How much did Mr A buy the car if x is $2800000 Answered by Penny Nom. 





The product of the coordinates of a point on a line 
20180117 

From Sophia: For any point on line l, the product of the xcoordinate and the ycoordinate is less than or equal to zero , what is the answer? Answered by Penny Nom. 





The decimal form of a fraction 
20180112 

From Tom: Prove that the decimal representation of the quotient of 2 integers must repeat (if it does not terminate). Answered by Penny Nom. 





When are the hands of a clock perpendicular? 
20180111 

From Nazrul: How many times in a day are the hands of a clock perpendicular to each other? How can I find the times? Please help me. Answered by Penny Nom. 





xy+x=2y. Solve for y 
20180110 

From Hugh: xy+x=2y. Solve for y Answered by Penny Nom. 





A fraction of a mile 
20180106 

From Sierra: There are 5280 feet in a mile. what fraction of a mile is represented by 660 feet? Answered by Penny Nom. 





2color combinations 
20180105 

From Sabrina: How many 2color (pair) combinations can be made from 12 individual colors... is it (11x12) or (optional): (11x12)x2? Answered by Penny Nom. 





Compatible numbers 
20180102 

From Natalie: I'm in 4th grade and two weeks ago my class learned how to use compatible numbers.
I was REALLY confused but I didn't want to say I didn't understand because I just wanted to go home.
Tomorrow we have the Topic 7 Test and I'm stuck on a problem that requires using compatible numbers.
My mom apparently hasn't heard of compatible numbers and she can't really help me too much.
Here's the problem : The local library places new books in a section with 31 shelves. Each shelf
fits 18 books. Use compatible numbers to estimate the number of books that the library can fit on
the shelves. Answered by Penny Nom. 





Speed in kilometers per hour 
20171221 

From Cody: if a train travels 400 meters in 30 seconds how many kilometers per hr is it traveling Answered by Penny Nom. 





A puzzling sequence 
20171219 

From Alan: My son has the following sequence to work out the formula for the nth term (and fing 5th and 6th terms) and I have tried a variety of ways but can't help!
1/2, 5/6, 1, 11/10
I have converted all to 15/30, 25/30, 30/30, 33/30 and so think the next two terms are 37/30 and 45/30 but I have no idea how to prove or if I am right!
Any help appreciated. Answered by Penny Nom. 





Retiring athletes numbers 
20171218 

From Robin: I am wondering if you can explain in layman terms how to figure out how many different ways the numbers 0099 can be arranged? The discussion that sparked this question revolved around the practice of retiring athletes numbers and how many actual number combinations there are. So if I were to use 00, 01, 02 03, 04, 05, 06, 07, 08, 09, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, ....99. I say there are only 109 different numbers. I'm being told I'm wrong that there are way more than that. Please help. Thank you, Robin Answered by Penny Nom. 





Matched pairs 
20171213 

From Lin:
PLEASE HELP WITH THIS VERY DIFFICULT STATISTICS QUESTION(the process would really help)
Imagine you and your 4 study group partners are interested in whether all
those hours you spent together working on statistics problems for midterm
exam 2 actually helped your group's performance on that exam relative to its
performance on the first midterm exam. Suppose the first and second midterm
grades were as follows:
Is there sufficient evidence (at a = :05) to conclude that the group performed
better on midterm 2? Please provide all your calculations.

midterm 1 
midterm 2 
A 
25 
28 
B 
20 
19 
C 
15 
21 
D 
16 
25 
E 
20 
22 
Answered by Penny Nom. 





4444^4444 
20171210 

From Sashi: 4444 to power of 4444=?
Please share the result with simplification. Answered by Penny Nom. 





Needing the area of an irregular Pentagon 
20171206 

From Dale: I'm needing to find the square footage of an irregular pentagon.
I've seen the other questions similar to this one, but without a great deal of difficulty can't get you the angle degrees, or the length between opposing angles.
I'm hoping that a different bit of information can help. So here goes:
The longest side is 67ft long.
One of its legs is 39ft long, and the other is 18ft long.
The leg off of the other end of the 39ft leg is 35ft long.
The leg off of the other end of the 18ft is 49ft long, and meets the other end of the 35ft side.
The information that I DO have, which I'm hoping makes the difference, is that the 39ft and the 18ft sides are parallel.
Also, while the angles at each end of the 67ft side are not right angles, they are fairly close to it,
approximately 80 degrees at the 39 ft side corner, and 100 degrees at the 18ft side corner.
Dale. Answered by Harley Weston. 





A range hood 
20171204 

From Chuck: I'm building a custom range hood and can't seem to get the angles correct where the front and side panels intersect.
I saw a similar post but there's no way I can do the calculations for a Wolfram Alpha!
Here are the dimensions that I have (in inches)...
Base  Front 29 7/16" x side 19 3/16"
Top  Front 10" x side 9"
Front Panel Length (from base to top on an angle) 21"
Side Panel Length (from base to top on an angle)  17 9/16"
Vertical distance from the base to the top 14 1/4 inches.
Any help finding the bevel/miter of the two front corners where the sides meet the front panel would be greatly appreciated.
I will need the angle for the saw in degrees.
Thank you in advance!
Regards,
Chuck Answered by Harley Weston. 





An arithmetic sequence 
20171130 

From yo: x; 2x+1; 11 are three consecutive terms of an arithmetic sequence.calculate x Answered by Penny Nom. 





The derivative of f(x)=2^x/x 
20171128 

From Chhavi: f(x)=2^x/x.
Find f'(x). Answered by Penny Nom. 





GCD 
20171125 

From A student: Suppose a,b, c are integers such that gcd(a,b)=gcd(a,c)=1. Show that gcd(a,bc)=1. Answered by Penny Nom. 





Abstract algebra 
20171125 

From A student: Suppose a,b, c are integers such that gcd(a,b)=gcd(a,c)=1. Show that gcd(a,bc)=1. Answered by Penny Nom. 





Exponential form 
20171125 

From Sherry: What is the exponential form of 3sqrt 15? Answered by Penny Nom. 





10 digit permutations 
20171124 

From Ed: HI my question..
numbers1,2,3,4,5,6,7,8,9,0 how many combinations are there
example: 518, 269, 3470
example2:815,972, 3460
example3: 185,047,2369 Answered by Penny Nom. 





Heat equation 
20171123 

From Max: What does du\dt=a(triangle)^2u mean. Can it be solved for t. Answered by Penny Nom. 





How many miles did he drive in one hour? 
20171121 

From Ava: Graham drove 42 1/3 Miles in 1 1/3 hours. How many miles did he drive in one hour? Answered by Penny Nom. 





An expression for the area of a triangle 
20171119 

From hari: why is area of a triangle drawn from centre of a circle i.e radii forming the sides is
1/2 *r^2 sin theta where r is radius Answered by Penny Nom. 





Jesse has dimes and nickels in his piggy bank. 
20171118 

From Dee: Jesse has dimes and nickels in his piggy bank.
The number of nickels is 3 times the number of dimes.
If the total amount is $8.50, how many coins are there in total? Answered by Penny Nom. 





Blair is 12 years younger than Serena right now. 
20171118 

From Dee: Blair is 12 years younger than Serena right now.
Three years ago Serena’s age was five times Blair’s age. What are their ages? Answered by Penny Nom. 





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. 





Splitting twice 
20171111 

From Terry: 4 people are splitting 1/3 of something. 1 is to receive twice as much as the other 3. what it the fractional interest for each? Answered by Penny Nom. 





The graph of graph y= 2x1 
20171111 

From Natividad: How do you graph y= 2x1? Answered by Penny Nom. 





A triangle with sides measuring 6, 8 and 10 inches 
20171111 

From rukhsar: A certain triangle has sides, which are, respectively, 6 inches, 8 inches, and 10 inches long. A rectangle equal in area to that of the triangle has a width of 3 inches. The Perimeter of the rectangle, expressed in inches, is Answered by Penny Nom. 





math 
20171111 

From rukhsar: A certain triangle has sides, which are, respectively, 6 inches, 8 inches, and 10 inches long. A rectangle equal in area to that of the triangle has a width of 3 inches. The Perimeter of the rectangle, expressed in inches, is Answered by Penny Nom. 





Five coins 
20171110 

From Allan: I have five coins..a penny,a nickle,a dime,a quarter and a loonie.....how many different amounts of money could i pay using ny combination of this coins Answered by Penny Nom. 





Mathematical ideas in everyday life 
20171108 

From Ricita: Mathematical ideas to solve various problems of our everyday life ,environment
related problems. Answered by Penny Nom. 





Scale factor 
20171103 

From Hannah: I do not understand it...... What is the scale factor for 9 cenimeters = 1 meter Answered by Penny Nom. 





Formula when i know the GST total 
20171031 

From Duncan: HI  I've added up the GST from a pile of receipts and would like to know what the total cost of goods would be without GST. I don't want to add up 100's of receipts again with the cost before GST but I do need this total cost.
i.e.) I know I paid $400 GST, what would the formula be to find out the cost of what I purchased before taxes? Your help is much appreciated! Answered by Penny Nom. 





formula when i know the GST total 
20171031 

From Duncan: HI  I've added up the GST from a pile of receipts and would like to know what the total cost of goods would be without GST. I don't want to add up 100's of receipts again with the cost before GST but I do need this total cost.
i.e.) I know I paid $400 GST, what would the formula be to find out the cost of what I purchased before taxes? Your help is much appreciated! Answered by Penny Nom. 





Surface area of a hemisphere 
20171028 

From Shaina: If the total surface area of a hemisphere be 36.22/7 cm then its radius will be 3 cm is it true or false Answered by Penny Nom. 





Adding fractions 
20171027 

From Sandy: virinchi distributed 4/7 of cake to his friends 1/3 of it to his family members which part of cake is remaining? 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. 





Solve 2cos^2 x + sin x = 2 
20171025 

From Yamama:
hello ! I need help to solve this equation :
2cos^2 x + sin x = 2
Thank you very much
Regards Answered by Penny Nom. 





11% of a central angle 
20171022 

From Hope: How do you turn a percentage in to a central angle eg. 11% Answered by Penny Nom. 





A tangent to a curve 
20171022 

From Jasem:
Suppose that
f(x)=(3x3)^1/2.
(A) Find an equation for the tangent line to the graph of f(x) at x=2
(B) Find all values of xx where the tangent line is horizontal, and enter them as a commaseparated list (e.g., 2,3,6). If there are none, enter none.
Values of x Answered by Penny Nom. 





Sampling distribution 
20171016 

From Esther: I need 4digits combination of 235689 and without replacement. Thanks 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 Veronika’s weekly gross salary if her total sales were ₱2050? Answered by Penny Nom. 





The distance between the origin and a moving point on a graph 
20171016 

From Paulina: Find the rate of change of the distance between the origin and a moving point on the graph of y=x^2 +1 if dx/dt=2 centimeters per second Answered by Penny Nom. 





Three consecutive odd integers 
20171010 

From Johanna: Three consecutive odd integers are such that the sum of the first and second is 31 less than 3 times the third Answered by Penny Nom. 





27000001 
20171009 

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





Five bales 
20171008 

From John:
two answers were given... I believe both to be incorrect.
five bales weighed two at a time: weightx2 given: 110,112,113,114,115,116,117,118,120, and 121. It stated all combinations ie: ab,ac,ad,ad,bc,bd,be, etc. to arrive at the above 10 combined weights. I come up with the following...
Bale A= 54lbs, Bale B=56, Bale C=58, Bale D=59. and Bale E=62 pounds.
A+B=110, A+C=112, A+D=, B+C=114, B+D=115 ,A+E=116 ,C+D=117, B+E=118 ,C+E=120, and D+E=121 Answered by Penny Nom. 





An enclosure for some remote control boats 
20171003 

From Roberto: I am trying to build a "ring" for our remote control boats, using irrigation pipe.
I'd like to use full 20' long sticks for the long sides and use eight of what we call
45s, which are actually 135' fittings to make the six short sides. If I know the length
of the two long sides, what would be the formula to find the exact lengths of the short sides?
Thank you. Answered by Penny Nom. 





The volume of a cone without calculus 
20171002 

From Akash: How to find the volume of a cone without the knowledge of calculus? 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. 





The importance of a comma 
20170930 

From carolyn: the equation 2y + 53 = 165 represents the situation joel spent 165 dollars on a pair of jeans and two shirts at the same price what does y represent
price of a pair of jeans
price of a shirt
amount joel spent on the shirts
number of shirts joel bought Answered by Penny Nom. 





Macy and Camile's ages 
20170930 

From carolyn: macy is 2 years older than Camille twice the sum of their ages is 52 which equation can be used to find camilles age x Answered by Penny Nom. 





How many pet dogs? 
20170926 

From Michelle: In 2016 there were about 135 million households in the United States. 36.5% of the households own at least one dog. On average, these households have 1.6 dogs. How many millins of pet dogs were in the United States in 2016? Answered by Penny Nom. 





Four multiples of 10 
20170923 

From Laudacir: Four multiples of 10 are added together.the total is a 3 digit number with three consecutive digits. What could the four number be? Answered by Penny Nom. 





Changing a mixed number to a decimal 
20170923 

From karla: to change an improper fraction into a decimal 5 3/4 equals Answered by Penny Nom. 





Walking up and down a hill 
20170919 

From Justina: At 2:20 p.m. Jack is at the top of the hill and starts walking down at the exact same time that Jill, who is at the bottom of the hill, starts walking up. If they maintain the uphill speed of 2mph and downhill speed of 4mph and the distance from the bottom to the top of the hill is 1.5 mi, at what time will Jack and Jill meet? Answered by Penny Nom. 





Up a hill and down again 
20170917 

From justina: Jack and Jill travel up a hill at a speed of 2mi/h.they travel back down the hill at a speed of 4mi/h.what is their average speed for the entire trip? express your answer as a mixed number Answered by Penny Nom. 





An alphabetic sequence 
20170917 

From malik: find the letter of the following series....?
ZOTTFFSSE Answered by Penny Nom. 





The surface area of a sphere 
20170917 

From penny: The surface area of a sphere is 1519.76cm. Taking 3.14 , find the radius of sphere 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. 





Peanuts in 5 bags 
20170917 

From Maria: There are a total of 270 peanuts divided up into five different bags. The first two bags contain 174 peanuts between the two of them. The second and third bags contain 130 peanuts between the two of them. The third and fourth bags contain 86 peanuts between the two of them. The fourth and fifth bags contain 42 peanuts between the two of them. How many peanuts are in each bag? Answered by Penny Nom. 





An equilateral triangle inscribed in a circle 
20170915 

From sumit: what is the area (in sq. unit) of an equilateral triangle inscribed in the circle x^2+y^24x6y23=0. Answered by Penny Nom. 





Complementary angles 
20170915 

From SM: The measure of angle A is 60 degrees more than its complement. Find the measure of angle A. Answered by Penny Nom. 





Average price 
20170915 

From Annette: If I sold a widget at $15.50 17.5% of the time and $16.50 88.5% of the time what is the algebraic expression for that. How do I arrive at an average price 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. 





The angle between two planes 
20170912 

From Arthi: Hello. hope you are having a good day.
I am stuck on a maths question in which it is asking, how to find the angle between two given planes. These planes are in a 3D shape such as a prism.
How can I do this?
Please reply as soon as possible
Thank You Answered by Penny Nom. 





Quadrilateral ABCD is inscribed in a circle 
20170911 

From Joie: Quadrilateral ABCD is inscribed in a circle such that side DA is the diameter. AB=2m., BC=4m., CD=6m., angle BAD=75.93degrees. Find the area of the quadrilateral. Answered by Penny Nom. 





A pool with a dome 
20170911 

From Bruce: A round 24 foot pool. A dome 3 feet above pool in center. How many feet across is the dome touching top rail straight across of pool? 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. 





The volume of an attic 
20170907 

From paul: trying to determine volume of an attic base is rectangular 29 ft by 37 ft
peak runs parallel to longest base side and is 7 ft long
roof lines run from each end of the peak to the respective corners
the peak is 3.5 ft above the base
(so seen from above there are 5 visible lines: the peak and 1 line to each of the 4 corners) Answered by Harley. 





Simultaneous equations 
20170902 

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





Prisms 
20170901 

From Christa: What do all prisms have in common? Answered by Penny Nom. 





Annual salary 
20170901 

From Lisa: I am applying for a job that pays $16.00 per hour, plus 5 hours of overtime every 2 weeks. I live in California, where overtime is 1.5 times the regular rate of pay after you work 8 hours a day. What would the gross annual salary be with all the overtime hours added in? Answered by Penny Nom. 





A rope formed in a semicircle 
20170829 

From Janna: How do I find the total length of a piece of rope formed in a semicircle that has a diameter of 8 inches? Answered by Penny Nom. 





A car on a rough road and a concrete road 
20170827 

From Ken: A car is driven on a rough road at a speed of 25km and then on a concrete road with a speed of 70kph. The car has 5.5 hours to travel 225km. How long did the car travel on concrete road? Answered by Penny Nom. 





Factors 
20170816 

From Gemma: Why do 315 and 525 have the same number of factors? 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. 





Two circles 
20170813 

From Ladines: Find the equation of the circle passing through points of intersections of circles x²+y²=4y and x²+y²=2x and the center is on line y=2 Answered by Penny Nom. 





A rectangle and a circle 
20170812 

From Ramzan: a diagram shows the shape of rectangular framework with length (2x+20)cm and with (y+10)cm . The outline is made of wire . If a circle with diameter 56 cm is to be made from the wire and the area of the rectangle is 420 square centimeter ,find the possible lengths and width of the rectangle Answered by Penny Nom. 





1 billion x 1 billion 
20170811 

From Kona: 1 billion x 1 billion
1 trillion x 1 trillion Answered by Penny Nom. 





The perimeter of a sector of a circle 
20170811 

From Alisa: find the perimeter of the sector with radius 7 cm in which the angle at the centre is 60 degrees leave your answer in terms of pi Answered by Penny Nom. 





Two digit numbers that contain 5 
20170811 

From Irish: How many two digit numbers contain the digit 5? Answered by Penny Nom. 





(x18)/7=6 
20170808 

From David: (x18)/7=6 Answered by Penny Nom. 





A pair of linear inequalities 
20170808 

From Hempstone: Solve the inequalities 3x5<2x+5>4x+9 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. 





Teams of 4 from 20 people 
20170804 

From Christopher: math team has 20 people on the team but only 4 can enter the competition. The team captain has to pick 4 of them but he knows that he cannot put James, Bill or Todd on the team with one another or there will be problems. what would the formula be to find the solution to how many possible team combinations the are Answered by Penny Nom. 





Ratios and proportions 
20170801 

From khurram: what is ratio and proportion? please give a detailed note on this topic, i am really panic of these calculations Answered by Penny Nom. 





A lock with 3 tumblers 
20170729 

From Carol: I have a lock that has 3 tumblers. The numbers are 0  9. I cannot recall what I set the combination to. How many combinations will there be with three numbers? Answered by Penny Nom. 





A 4 digit safe combination 
20170729 

From Donna: I lost my safe combination :( it is 4 digit # with the last digit being 2.
I do not think the 1st digit is 1, 2 or 3
Can u help? Thank u :) Answered by Penny Nom. 





Factorials 
20170727 

From dinesh: Is there any shortcut formula for multiply series numbers.
like
1x2x3x4x5.......x100 =? Answered by Penny Nom. 





A semi ellipse 
20170725 

From Ian: The arch of the bridge is in the shape of semi ellipse,with its major axis at the water level.suppose the arch is 20ft. High in the middle,and 120 ft. Across its major axis. How high above the water level is the arch,at a point 20 ft.from the center (horizontally). Round of 2 decimal places Answered by Penny Nom. 





An arched window 
20170724 

From Gerry: Looking to make a full size template for an arched window. Need increments every 16". The radius is 138' 0 9/16" , the chord is 226" and the rise at center of chord is 43" Answered by Penny Nom. 





Some 4 digit numbers 
20170724 

From Camille: I need all of the 4 digit combinations that starts with number 3 and digits can't be repeated Answered by Penny Nom. 





3 consecutive multiples of 11 
20170722 

From nisha: using the multiples formula shown at ypur site how can we solve finding 3 consecutive multiples of 11 whose sum is 363 Answered by Penny Nom. 





A police officer spots a speeding car 
20170720 

From Josh: Marie, a police officer, spots a speeding car and starts chasing it. The speeding
car travels at a speed of 130 feet per second. Marie's car reaches a constant speed
of 145 feet per second 1725 feet from the start of the chase. During that time, the
speeding car has traveled 3150 feet. Write a system of equations to represent this
situation. Answered by Penny Nom. 





Catherine, Molly and Tom 
20170719 

From liezel: what is the answer of this problem, If Catherine and molly has 320pesos altogether, Molly and tom have 360 in all. Tom and Catherine have 240pesos altogether.How much does each of them have? Answered by Penny Nom. 





((a5)/a)/(4/a) 
20170718 

From Michael: Find the Quotient:
((a5)/a)/(4/a) Answered by Penny Nom. 





Parallel and Perpendicular lines 
20170717 

From Karen: Find an equation for the line with the given properties. Perpendicular to the line 7x + 2y = 6; containing the point (2, 1)
Find an equation for the line with the given properties. Parallel to the line 5x  3y =6; x intercept = 3 Answered by Penny Nom. 





An arithmetic sequence 
20170717 

From abbi: hi there im a student in 11 grade
ive been trying to do this task but i have no idea how to do it
the question is
Find the common difference and the n^th term of the arithmetic sequence if the first term is 4 and the twentieth sum of the terms is 1030 Answered by Penny Nom. 





Squares and rectangles 
20170715 

From Tront: So, there's a general rule that all squares are rectangles but not all rectangles are squares. Im trying to find a term that would describe this relationship. I've found that if all of A is B but not all B is A then I'd say that A is a subset of B, but is there a term that describes the relationship as a whole? I don't want to describe the components, I want to describe the relationship as a whole. Answered by Penny Nom. 





Two consecutive odd integers 
20170714 

From Adeeb: Find two consecutive odd positive integers, sum of whose square is 290. Answered by Penny Nom. 





Exponential form 
20170706 

From estela: what is exponential form of 9×1000 Answered by Penny Nom. 





Of cows and men 
20170704 

From Akash: In a group of cows and man the number of legs is 32 more than the twice the number of heads.The number of cows is? Answered by Penny Nom. 





The equation of a circle 
20170703 

From Chen: Find the center radius and equation of a circle in standard form given the following conditions:
1. Tangent to 3x+2y=0 at the point (0,0) and passing through (1,1) and (6,0) Answered by Penny Nom. 





y = g(x + 1) 
20170627 

From Shamsudiin: HI there i am currently doing a level maths AS
I don't understand how to graph this Question y=g(x+1) i really need help please
please respond to this problem Answered by Penny Nom. 





How fast am I travelling? 
20170624 

From corey: if i travel 2 miles in 10 seconds, how fast am i travelling please Answered by Penny Nom. 





The number of truckloads to fill a hole 
20170618 

From Jennifer: How many full size truck bed pickup loads do in need to get to fill a hole that is 18' x 30' that is 4" deep? 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. 





The surface area of a hexagonal pyramid 
20170616 

From Emilie: Hello, I need help with this question:
A pyramid has a regular hexagonal base with side lengths of 4 and a slant height of 6. Find the total area of the pyramid.
Thank you in advance if you can help me... Answered by Penny Nom. 





What percentage did I take? 
20170614 

From david: you have $5.85 I took $1.06 from you,what percentage did I take? and the formula to solve it. Thank you Answered by Penny Nom. 





The smallest and largest 4 digit integers 
20170613 

From Avneetpal: Difference of the smallest and biggest 4digit number Answered by Penny Nom. 





Three consecutive natural numbers 
20170611 

From Anita: Three consecutive natural numbers are such that the square of the middle number exceeds the difference of the square of the other two by 60. Find the numbers. 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. 





A man drives 48km in 45 minutes 
20170603 

From Jamal: A man drives from Ibadan to Oyo a distance of 48km in 45 minutes. If he drives at 72km/h where the surface is good and 48km/h where the surface is bad. Find the number of kilometers of good surfaces 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. 





The maximum area of a rectangle with a given perimeter 
20170602 

From Bob: How would I go about finding the maximum area of a rectangle given its perimeter (20m, for example)? Answered by Penny Nom. 





4 digit codes with repeating digits 
20170601 

From Morgan: what are all possible 4 digit code repeating numbers? cuz i know that you have one website on it but, it doesn't repeat 2 numbers in a code. Answered by Harley. 





A cylindrical water tank with a leak 
20170601 

From Alexander: if a cylindrical water tank has diameter of 90cm and leak starts at the bottom 10 litres in an hour. how long will it take for the level to fall by 20cm Answered by Penny Nom. 





Five rational numbers between 2 and 1 
20170531 

From Prince: Five rational numbers between 2 and 1 Answered by Penny Nom. 





3rd Grade math problem 
20170530 

From Angela: Following is a problem from my 3rd grader's homework assignment:
Solve. Draw a diagram to represent the situation.
Rachel has 20 oneinch beads. She wants to use all of them to make a square picture frame. What will be the length of each side?
Find Perimeter, Area, and Side Length Answered by Penny Nom. 





A square peg in a round hole 
20170529 

From bill: bill wants to put a 2 foot square peg into a round hole What must be the circumference of the hole? Answered by Penny Nom. 





A 25 acre strip 
20170529 

From Va: hello, can you pls help me....i have a property which has 300 ft width road frontage and my lot is 4700 ft deep to the back line of my property which i am told 27 acres. I want to only sell 25 acres...and go to the rear line with 4700 feet, but decrease the front width using the 300 ft measurement. how do i decrease the 300 ft width measurement by 2 acres? i am confused what the measurement would be..thank you....so to sum it i want to make 25 acres out of a measurement of 300 x 4700 ft long reducing the front measurement..thank you so much. Answered by Penny Nom. 





Algebra 
20170528 

From Kerim: I need to solve this equation.
y=at^2  2at
x =2a√t
Express y in terms of x and a
Give in the form y=(x^p/ma^3)  (x^q/na) where p,q,m and n are integers Answered by Penny Nom. 





A polygon inscribed in a circle 
20170527 

From Levan: This was the closest to what I am trying to solve.
http://mathcentral.uregina.ca/QQ/database/QQ.09.06/s/dj1.html
So in the answer linked, we figure out what is "c".
But what if we know "c" and want to find out "n" based on specific "r=1".
It might be simple math, but I have not had any relationship with math for 20 years now
but this question puzzles me for a reason. Answered by Penny Nom. 





Ordering fractions 
20170525 

From Esmeralda: How May i order this 30%,3/100,7/20 and 0.33 from least to greatest Answered by Penny Nom. 





Initial velocity 
20170523 

From Annelle: a body is thrown vertically downward from a height above the ground. determine the initial velocity and the height of the starting point if after 4 secs it reaches the ground with velocity of 68 m/s. Answered by Penny Nom. 





A trapezoid inscribed in a circle 
20170517 

From Kameron: I have been given a challenge problem that states that Diameter AB is drawn in a circle if 10 inch. Chords AC and BD are drawn so that each is of length 12inch and ACDB is a trapezoid. Find the height, in inches, of the trapezoid Answered by Penny Nom. 





A 40 acre square 
20170514 

From Richard: How many feet on each side of 40 acre square ? Answered by Penny Nom. 





A limit 
20170514 

From Soham: Find out the value of the following:
lim (x+x^2 +x^3 +.........x^n–n)/(x–1)
x→1 Answered by Penny Nom. 





Two wires between two buildings 
20170511 

From Bill: I need to find the height of the intersection point of two building wires< br />
Building A is 860 feet high and building B is 480 feet high. The wires existent from the top of one building to
The bottom of the other < br />
The distance between is 32 feet Answered by Penny Nom. 





What is the regular price? 
20170511 

From Saira: If the sale price is 55.50$ and the discount is 12% what is the regular price Answered by Penny Nom. 





Canada's population as a percentage 
20170511 

From bethmarie: What percentage of the world population (7.5 billion) is Canada's population (36 million).
Thank you very much! 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. 





Slicing an inverted bowl at various heights 
20170430 

From Joel: Find a formula to calculate the circumferences of an inverted bowl at various heights.
E.g. Take an inverted bowl with a diameter of "x" cm and a depth / height of "y" cm.
How can I calculate the circumferences at distances of various heights above the base?
Alternately, what would be the formula to calculate the distance of the line segment resulting from a line which intersects both sides of a parabola in which that line is drawn parallel to the tangent of the vertex of the parabola at any given distance from the vertex? Answered by Penny Nom. 





Jamie has twice as many video games as Mel. 
20170427 

From John: Jamie has twice as many video games as Mel. Together, the boys have 24 games. how many games do each boy have Answered by Penny Nom. 





1 acre as a 2 foot wide strip of land 
20170425 

From alan: How can one convert 2 acres (a square  area) of land into a strip of land that is 2 feet wide and (?) feet long? Answered by Penny Nom. 





Filling cinder blocks with concrete 
20170424 

From Katherine: I am looking to construct a 10 X 10 dance floor using 8 x 16 cinder blocks.
I have figured that I will need about 120 blocks, however I am not sure
how much concrete I will need to fill the total empty space.
Thank you Answered by Penny Nom. 





Selling price and markup 
20170424 

From Julie: What would the cost of an item be, if the sell price was $50 and the markup 48% Answered by Penny Nom. 





The length of a train 
20170424 

From Stefano: If a freight train is coming towards you and you were traveling at 85 miles an hour and it takes 35 seconds for the train to pass you how long is the train
Figure 50mph for train Answered by Penny Nom. 





Baseball Cards 
20170420 

From Raquel: A minor league baseball team gave away baseball cards to each person entering the stadium. One group receives 28 baseball cards. A second group received 68 baseball card. If each person entering the stadium receive the same number of cards, what was the greatest possible number of baseball cards that each person could have received? Answered by Penny Nom. 





A lost iPhone pass code 
20170417 

From Sam: I have a locked iPhone and it has all my of my holiday photos on it. I changed the password and then I think I did a incorrect number pattern but anyway I know it ends with 99 and the first 4 digits are 235 and 6 could you please send all of the combinations for this password (without the 99) Thx and plz get back ASAP I need it for school Answered by Penny Nom. 





sin x/ 1+cos x = 1cos x/ sin x 
20170416 

From duiren: sin x/ 1+cos x = 1cos x/ sin x Answered by Penny Nom. 





A function which is onto but not onetoone 
20170416 

From Avinash: Define a function f(x):N>N which is onto but not oneone.Where N is set of natural numbers. Answered by Penny Nom. 





A word problem about the dimensions of a lot 
20170416 

From Charlotte: If a house is 66x78 ft, how many feet out from the house around would be an acre to not include the house Answered by Penny Nom. 





Forming a cone from a circle 
20170415 

From Tasha: A sector of a circle subtends an angle of 216 degrees at the centre, If this sector is used to form a cone of vertical height ,8cm, calculate the base radius of the cone Answered by Penny Nom. 





Express x/a 2a/x =1 in terms of a. 
20170414 

From tony: express x/a 2a/x =1 in terms of a. Answered by Penny Nom. 





The cost of a piece of sheet metal 
20170414 

From Mohammed: I bought a 2 mm sheet plate of 1.2m × 2.4m in fijian $95. I used 1.95m × 0.4m from that sheet plate. What will be my total cost for the sheet plate I used. It was a mild steel plate. Answered by Penny Nom. 





Why does 10x10x10 give 1,000.0000000000001? 
20170412 

From Randolph: Hi, On your calculator I found that a box 10 by 10 by 10 inches has a volume of 1,000.0000000000001 cubic inches. Can you explain the numeral 1 thirteen places past the decimal? Thanks, Randy Answered by Penny Nom. 





Acres and perimeter 
20170412 

From Peggy: How many acres in 2700' circumference or perimeter Answered by Penny Nom. 





A rectangular box filled with oil 
20170411 

From morpal: we want to calculate volume of rectangular box height 1275mm and lengths 2400mm and breadth 1270mm and oil s. gravity is .950 how much kg. of oil i can store Answered by Penny Nom. 





Rational numbers between 2 and 3 
20170408 

From Medha: Find 12 rational numbers between2 and 3 Answered by Penny Nom. 





A circle inscribed in a 30690 triangle 
20170407 

From Kameron: i have been given a problem with a 306090 triangle and a circle inscribed with a radius of 2 and was told to find the perimeter of the triangle 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. 





The height of a isosceles trapezoid 
20170403 

From Riham: Hi
How can I find the height in an isosceles trapezoid if I have the measurements of all of its sides ?
Thank u in advance. Answered by Penny Nom. 





How to find last two or three digits of a large exponent like 17^256? 
20170330 

From Raginee: How to find last two or three digits of a large exponent like 17^256? Answered by Penny Nom. 





A puzzle with some integers 
20170330 

From Glen: Use 7,7,5,5 to equal 3 only using each # once and each math function once Answered by Penny Nom. 





13  3x = x times the square root of 5 
20170329 

From Kevin: A student I am tutoring was sent this question from his teacher.
Solve for x: 13  3x = x times the square root of 5 Answered by Penny Nom. 





Is the square root of 2 plus the square root of 2 irrational? 
20170329 

From haya: how can i prove the the square root of 2 plus the square root of 2 is an irrational number? Answered by Penny Nom. 





How much money do I make per sq ft? 
20170328 

From jackie: If I make $12.00 per hour and I cover 750 sq ft in one hour, how much money do I make per sq ft? 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. 





Quadratic Equations 
20170328 

From Natalie:
Hi Maths Central,
I am having trouble with quadratic equations. The question is:
Calculate the length 'l' of a rectangular pool by creating and solving a quadratic equation.
1. The rectangular pool is of equal area to a square pool, and a circular pool (5.70m^2).
2. The length of the rectangular pool must be 2m longer than the width 'w'.
Thank you so, so much for your help, Maths Central! Answered by Penny Nom. 





The sum and difference of two numbers 
20170320 

From Olivia: The sum of two numbers is 87 and their difference is 29. What are the two numbers Answered by Penny Nom. 





Differentiate y = x^x^x 
20170319 

From Nafis: differentiate y = x^x^x Answered by Penny Nom. 





Is infinite a number? 
20170318 

From Divyansh: Is infinite a number? If yes why as i think that numbers are used for counting but infinite is undeterminable? Answered by Penny Nom. 





Faster than as a percentage 
20170318 

From Maximilian: Hi, i have a strange issue with the phrase "faster than" in percentage, ie. if i have a 10MB/s connection, and somebody has a 7MB/s connection, is it 30% faster or 50% faster.
which ( affirmation, phrase, sentence ) is the right one:
a:) My 10MB/S connection is 50% faster than the 7MB/s ?
or
b:) My 10MB/S connection is 30% faster than the 7MB/s ?
Thanks in Advance, and please if you can teach me why ! Answered by Penny Nom. 





2^a, 2^b, 1^1 and 1^0 
20170317 

From Émile: If you had 2^a = 4 and 2^b = 4 you could assume that a = b right? Yet we can observe that 1^1 and 1^0 both equal 1, yet 1 = 0 isn't true. So if given a log base 1 number 1 the would the answer be 1 AND 0? Answered by Penny Nom. 





Percentage change in productivity 
20170315 

From Sunni: I'm working on a graph and I need to find the percentage of increase from one figure to another. How do I do that? For instance our department started with a workload of 1773 in Jan and ended with 341 in Dec. In addition to that we received 2088 new items from Jan  Dec with an average of 5 workers. How do I find the percentage of increased productivity if any? Answered by Penny Nom. 





Solve 3x^219x14=0 for x 
20170315 

From nick: I'm an 8th grader and am quite confused with this equation:
3x^219x14=0
The answer is:
2/3 , 7
But I'm not sure how to solve for it. Answered by Penny Nom. 





The ratio of two ages 
20170315 

From Angel: The sum of Keith's age and Alan's age is 36. Four years ago, the ratio of Keith's age to Alan's age was 4:3. Find the ratio of their present age Answered by Penny Nom. 





What is the grade of the incline? 
20170312 

From Jon: If I am climbing 16 feet in elevation over 80 feet horizontal. What is the grade of the incline Answered by Penny Nom. 





A regular tetrahedron 
20170312 

From Jeramie: When we have a regular tetrahedron, is it always true that all the angles of the triangles measure 60 degrees? Answered by Penny Nom. 





How much does the fish weigh? 
20170308 

From Jeri: Fish is caught that weighs 5 pounds plus half its weight. How much does the fish weigh? 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. 





Exponential form 
20170304 

From michael: I was teaching my student about exponent when we stumbled across this problem.
"write (125)^3 in exponent form"
The problem is with the number "125". I think 125 = (5)^3. But one of my student thought that it is 125= 5^3.
Both of them is equal to 125 but they totally different in structure. I wonder which one is correct and why it is. I am worried if they get this wrong, it might spell problem in the future when we start substituting the numbers with variable.
Thank you very much for reading my question and answering it. Answered by Penny Nom. 





Tons of sand 
20170301 

From Elizabeth: Hello my arena is 132.23 feet width by 132.23 feet length. I need to put 4 inches of sand. How many tons of sand do I need ? 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. 





Building a hexagon enclosure 
20170226 

From Kenneth: Hello, I have a question for you. I have a special needs daughter and I want to install a ceiling fan into her room. The fan is 42 inches in diameter. I would like to build a wooden hexagon enclosure to protect the fan. I would like the enclosure to be at least 2 inches wider than the fan on each side measuring from flat surface across to flat surface. How do I figure out the length of each panel so that I can miter them and assemble it? Thank you for your time. Answered by Penny Nom. 





Covering a ceiling with tablecloths 
20170224 

From DEANNA: I am trying to cover a 16 x 31 foot ceiling with tablecloths. For sale, are 90 x 132 inch tablecloths for $4.97 a piece and 60 x 102 inch tablecloths for $3.85 a piece. Which would be my cheapest option to cover the entire space? Answered by Penny Nom. 





Filling a pool with two hoses 
20170220 

From Charlene: A large hose will fill a pool in 40 minutes while it takes a smaller hose 60 minutes to fill the same pool. The same pool takes 80 minutes to drain if the drain is open. Suppose one day both the hoses are turned on, but by accident the drain was left open. How long would it take to fill the pool that day? Answered by Penny Nom. 





Covering the ceiling of a garage 
20170220 

From DeAnna: I am trying to drape a 15 x 30 garage with yards of fabric. If the yard of fabric is 60 inches wide, would 10 1/4 yards be enough for my space? Answered by Penny Nom. 





A total amount of $27,500 invested at 5% and 7% 
20170219 

From Brad: Kristina invests a total of $27,500 in two accounts paying 5% and 7% simple interest, respectively. How much was invested in each account if, after one year, the total interest was $1,645.00. Answered by Penny Nom. 





A block base for a plywood rectangle 
20170218 

From Joe: How many cinder blocks 16x8 would i need to build a solid base for a plywood base 54inches wide and 30 inches deep Thank you Answered by Penny Nom. 





Addition and subtraction base 5 
20170129 

From BABAWALE: Simplify 342five +132five223five Answered by Penny Nom. 





Vinculum 
20170127 

From Dick: What is the line or bar over a Roman Numeral called?
Eg. V with the bar over it representing 5,000 . Answered by Penny Nom. 





Feet per second to miles per hour 
20170127 

From ron: if a vehicle travels 50 feet in 2.5 seconds what is the speed in mph.
3600 sec in hour /5280 feet in a mile i get .68181818. how do i figure the 2.5
seconds. all the calculators I've used show 34 mph is that correct or am i forgetting the 2.5 second. please help. Answered by Penny Nom. 





The volume of a slab 
20170121 

From Russell: Working with a segment of a circle. The O.D. is 3.440" the length of the chord is 3.130 I need information on the volume of the largest area. I would like to know (in thousands of an inch) how tall would the largest area need to be to equal .1143 cubic inches If you need more info I can send it Thanks in advance Answered by p. 





Angular speed 
20170121 

From Kenzi: A wheel of radius 14 inches is rotating 45°/sec. What is the linear speed in in/sec and the
angular speed in RPM? (Round your answers to three decimal places)
I already found the linear speed. I got 10.996 in/sec. I don't know how to find the angular
speed. Answered by Penny Nom. 





The ratio of students to teachers 
20170120 

From Dylan: The ratio of students to teachers at a school is 19:1. How many students are there in each total number of people? Answered by Penny Nom. 





The average rate of change of cot(t) 
20170118 

From Brianna: Hello!
It's been a while since I've taken a math course, and I'm stuck on a problem in my calculus course.
The question is this:
Find the average rate of change of the function over the given interval.
h(t)=cot(t) a) [5pi/4, 7pi/4] Answered by Penny Nom. 





Five equations 
20170116 

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





Form the quadratic equation which has given roots 
20170116 

From Tharshini: Given a and B are the roots of the quadratic equation x^2+4x+7=0. Form the quadratic equation which has the roots
3a1 and 3B1 Answered by Penny Nom. 





One millionth of one percent of 90,000,000,000 
20170116 

From Gene: What absolute number is one millionth of one percent of 90,000,000,000 Answered by Penny Nom. 





How do I establish the original List Price? 
20170115 

From Bob: (1) I have a net price item at $4,664.66 but do not have the discount percentage. I have been told I received 40%? How do I establish the original List Price and to confirm what discount I received? Answered by Penny Nom. 





A circle inscribed in an isosceles triangle 
20170114 

From Sal: There is a right isosceles triangle. Inscribed inside of it, is the largest possible circle.
Ho do you find the value of the radius?
I want to find out a way of only using the rules/laws of geometry, or is that not possible. Answered by Penny Nom. 





8^3/2(2+2) 
20170113 

From Mary: 8^3/2(2+2) Answered by Penny Nom. 





A rectangle with a given perimeter and area 
20170111 

From Joe: i have a math question for homework that i don't understand.
can you draw a rectangle that has 18cm in perimeters and 20cm in areas.
i tried but i can't. Answered by Penny Nom. 





An angle and its complement 
20170110 

From Ysa: If the measure of an angle is twice the measure of its complement, what is the measure of the angle? Answered by Penny Nom. 





Renting an electric cart 
20170107 

From Desiree: Vacation Rentals rents electric carts for travel on their grounds. The economy plan rents
carts for $26 per day and the premium plan rents a carts for $12 per day plus a one time fee of $126.05
For how many whole days would it be cheaper to rent from the economy plan then from the premium plan? Answered by Penny Nom. 





A tolerance limit is 0.5% 
20170106 

From Joe: Dear Sir/Madam,
How can I describe the following.
My volume tolerance limit is 0.5%,regardless of quantity.
Say , My total volume output is 344,714 Litres and benchmark volume is 348,194
Difference of 3480Litres, this would give me a percentage of 0.999.
Which is above my tolerance.
How can I explain this high tolerance limit even though volume difference is minimal.
Regards
Joe Answered by Penny Nom. 





A parabolic arch 
20170105 

From Rand: It is most likely already been answered but I can not seem to find the right key words for the search engine?.
What I am looking for is, if you have an have arch/arc and you know the degree of slope and the height of the arch/arc from ground lvl; how do you factor the decreasing angle/#’s to get the distance tween the two feet on the assumption that the arch/arc is curved all the way to ground lvl?
a. where the legs widen continuously (till they hit ground) so yes parabolic &
b. where the legs come down straight after a ½ circumference run.
What I am focusing is the parabolic.
Many Thanks Answered by Harley Weston. 





Plans for dog kennels 
20170104 

From Pat: So... I'm trying to draw up a plan for my new kennel buildings. They are going to built
out of grain bins. I know, cool,... right. Anyway the kennels will be along the outside
of the circle and be shaped like wedges. the center will be a play area. All of the kennel
sides are 6 ft in length so the size of the gate will determine how many kennels I can
fit in each bin. If I want to put an odd number of kennels in and I cant draw
a straight line across to make all of the wedges the same size... how do I figure out the
angles...degrees ? maybe i'm making it too hard but i'd like to give the dogs as much space
as i can. I did up some ... attached. Answered by Harley Weston. 





A rational number between 4 and 5 
20170103 

From Anshika: Write rational number between 4 and 5 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. 





Water leaking from a trough 
20161228 

From Kathryn: A trough is 6 m long, and has uniform crosssection of an equilateral triangle with sides 1 m.
Water leaks from the bottom of the trough, at a constant rate of 0.1 m3/min.
Find the rate at which the water level is falling when the water is 0.2m deep. Answered by Penny Nom. 





An octagon from a square 
20161226 

From Chris: We have a square piece of wood (30 inches x 30 inches) that we need to cut into an octagon. Is there a simple way to figure out where to make the marks/points to cut? I mean like really simple?
Thanks! Answered by Penny Nom. 





20+30*0+1=? 
20161226 

From Mr: 20+30*0+1=? Answered by Penny Nom. 





Write these numbers from greatest to least 
20161222 

From lsaiah: write the following numbers from greatest to least
3 1/2, 7/3, 80%, 2.5, 0.94 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. 





Two concentric circles 
20161221 

From shrestha: Two concentric circles have radii of 14 cm and 7 cm respectively. Find the area of space between them. Answered by Penny Nom. 





The inverse of y=x^2+x+c 
20161221 

From Sam: What is the inverse of y=x^2+x+c for x? Answered by Penny Nom. 





The inverse of y = x(x  2) 
20161221 

From Sasha: Hello, I recently stumbled upon this question and I haven't been able to figure it out.
Why is the inverse of y=x(x2) not a function?
Suggest a domain restriction which would ensure that the inverse is a function.
Thank You :) Answered by Penny Nom. 





The area and radius of a circle 
20161219 

From india: How do you find the radius of a circle if only the area is given to you? Answered by Penny Nom. 





Joining a fitness center 
20161218 

From Salem: A fitness center offers a special price for groupclass students. The cost of registration is 30 dollars and then you have to pay 25 dollars per month. What is the rule of the equation in the light of c=m+? Answered by Penny Nom. 





980 cubic yards of dirt 
20161217 

From Jondi: I am trying to visualize 980 cubic yards of dirt by using a metaphor.
Would this be the size of a car?
A fire engine?
A semitrailer?
How many trucks would you need to haul away 980 yards of dirt? Answered by Penny Nom. 





1/1cosine(2x)  1/1+ cos(2x) 
20161214 

From Sean: 1/1cosine(2x)  1/1+ cos(2x) 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. 





3^2x5=27 
20161214 

From danaja: solve for the following 3^2x5=27 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. 





x^2 = 16 
20161212 

From A student: x to the second power = 16
what number solves the equation? Answered by Penny Nom. 





The area of a city block 
20161208 

From Miura: A city block is three times as long as long as it is wide.if the distance around the block is 0.48 kilometers, what is the area of the block in square meters? Answered by Penny Nom. 





A sales tax of 7% 
20161207 

From Kenneth: Hello:
If a sales tax of 7% is placed on every $1.00 of merchandise for sale, is it correct to indicate
the tax as 7%/ per $1.00 or 7%/$1.00? If the calculation is expressed as 7%/$1.00 X $5.00,
the tax is not $0.35 but 0.35. Is a tax rate of 7% incorrectly represented as 7%/$1.00
since the dollar unit cancels from the multiplication?
I thank you for your reply. 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. 





Profit and loss on two shirts 
20161206 

From Mahesh: A man purchases one shirt and one TShirt for Rs. 6000. He sells the shirt at a profit of 20% and TShirt at a loss of 10%, as a result he gains 2% on whole transaction. what is the cost price of the TShirt ? Answered by Penny Nom. 





Two boys on the same route 
20161206 

From Abbey: Starting from the same spot, one boy completed a route in 9 minutes and another boy completed it in 15 minutes. When will both boys be at the same starting point at the same time again? Answered by Penny Nom. 





Three friends bought 13 books 
20161206 

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





Gallons and cubic inches 
20161205 

From Theresa: If I did not know the cubic inches in a liquid gallon how would I find it?
In other words what is the formula for this? 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. 





Covering a floor with plank flooring 
20161204 

From sandra: my bathroom is 5'x6'.2"
i want to purchase plank flooring which covers 19.8 sq ft per box.
how many boxes would i need. Answered by Penny Nom. 





The diagonals of a cube 
20161202 

From Peter: when u have a cube and the inner diagonal is 41.6 how long is the outside diagonal Answered by Penny Nom. 





Building a pyramid 
20161201 

From Jesse: I'm trying to build a 30"by30"by 18.25"tall pyramid,what should my cutting measurements be? Answered by Harley Weston. 





Acres and miles 
20161130 

From Carolyn: If I am running a pipeline of 1,100 miles, how many one acre plots will it take to cover this distance?
Carolyn Answered by Penny Nom. 





Is every rectangle a rhombus? 
20161128 

From Robert: not every rectangle is a rhombus.true or false? if false please leave a short explanation. thank you:) Answered by Penny Nom. 





A stone walkway around a garden 
20161127 

From Abigail: A garden measures 12 feet by 16 feet. The family would like to add a stone walkway around the garden. This would increase the total area of to 302.25 square feet. what will be the width of the of the walkway Answered by Penny Nom. 





Two tangent circles 
20161127 

From mikee: find the equation of a circle tangent to the circle x2+y2=4
and with the center at (0,5) Answered by Penny Nom. 





A circle inscribed in an equilateral triangle 
20161127 

From jo: what is the radius of the inscribed circle of an equilateral triangle with altitude 12 units? Answered by Penny Nom. 





2^x= 2x  11 
20161127 

From Kathy: I don't know how to start this problem:
2^x= 2x  11 Answered by Penny Nom. 





The weights of two boxes 
20161125 

From dearbhla: One box weighs 3 3/7kg. Another box weighs 1 5/6 as much. How heavy is the second box? 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. 





Radius angle and arc length 
20161124 

From pavidthra: Length or arc 11 and angle of subtended 45.need to find a radius Answered by Penny Nom. 





Multiplication and repeated addition 
20161123 

From Anandmay: Hello
I was looking closely at early arithmetic where I found how we discovered properties of Arithmetic.
Like:2 x 3 = 3 x 2.
This can be proved by considering a 2D figure(actually,quadrilateral) having length consisting of 2 boxes of
1by1 dimensions and breadth of 3 boxes of the same dimensions.
Now,consider it again,but,this time,length of 3,and breadth of 2 of such 1 by 1 boxes.
We now notice that we can fit the 2 types of rectangles formed on each other precisely.
So the multiplicative property of commutativity is true for all natural numbers as we can generalize the result(in our mind,for self satisfaction).
Now,can you find me a nice satisfactory reason of why a fraction times a natural number equals the number times the fraction?
I mean, for example,i can understand the meaning of 3 x 2/3 to be three times 23rd,that is, 2/3+2/3+2/3.Fair enough.
But here is the problem:By definition and actual meaning of multiplication, a x b means the repeated sum of b,done 'a' times.
So what is the meaning of doing 2/3 x 3?The repeated addition of 3 how many times??2/3 times??Not making sense,right?And even
we have not proved yet the commutative property of numbers INCLUDING fractions.So how can we resolve this problem and make these things meaningful?
Thanks Answered by Penny Nom. 





Why are equivalent fractions equal? Part 2. 
20161122 

From Anandmay: Hi!
I saw one of your answered questions:Why are equivalent fractions equal?
The same question I had for why i searched and ended up entering this wonderful site.
The answer was so much experimental based.I mean,for example,it was explained how
3/4 was equal to 6/8 by dividing a unit into 4 equal parts and taking four of the parts,and then dividing the
same unit into 8 equal parts and then taking 6 of them.The result was that both the taken parts were equal.
(That is,3 out of 4 equal parts were equal to 6 of the 8 equal parts.)
But,this was very much nongeneralized and experimentalbased result(proof).
And we all know that in mathematics,we confirm some particular thing for all the numbers iff we generalize
it.
So,can you explain more clearly 'HOW' the 3 parts of the 4 equal parts and the 6 of the 8 equal parts of the unit
equal(that is the same)?I don't want experimental proof.I want clear proof,and thus please give a generalized
proof for all fractions and their equivalents.
Thanks! 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 fish and eight parakeets 
20161111 

From Cindy: Cindys fish weighs 8 times as much as her parakeet. Together the pets weigh 63 ounces. How much does the fish weigh? Answered by Penny Nom. 





4444 base five 
20161111 

From John: If 4444 is a number in Base5, is 624 its value? Answered by Penny Nom. 





An equation with fractions 
20161109 

From Tina: How do you solve x+1/3=x+2/5. X+1 divided by 3= x+2 divided by 5. What's x= Answered by Penny Nom. 





Volume of liquid remaining in a tilted cylinder 
20161108 

From Brian: I am trying to determine the amount of a liquid remaining in a 55 gallon drum when it is tilted at 45 degrees and the liquid level is low enough so that the liquid does not completely cover the bottom of the drum.
Your help is greatly appreciated. Answered by Harley Weston. 





The area of a rectangle 
20161105 

From Ivan: If the vertices of a rectangle are a(1,3),b(3,4),and c(1,4),find it area. Answered by Penny Nom. 





A key for a lock with five tumblers 
20161102 

From Aeriel: A lock works by having a key turn a sequence of tumblers. Consecutive tumblers have different heights, and in order to unlock the lock, the sequence of heights on the key must exactly match those of the lock. The picture below shows a lock with four tumblers.
How many different keys can be made for a lock that has 7 tumblers with 5 possible heights each? Answered by Penny Nom. 





A problem with a recipe 
20161031 

From Ted: Recipe calls for 3 1/2 c of sugar & 4 c of water. I only have 3c of sugar how much water do I use Answered by Penny Nom. 





Three circles 
20161030 

From yolani: two equal circles with centre A (1;1)and B (4;5)touch a third circle with centre P as shown in the diagram. If P ,A and B Lie on a straight line find the coordinates of P 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. 





The derivative of the inverse of a function 
20161028 

From Kate: Hi, I'm in a College level Calculus course and I can't seem to figure out the answer to this question.
Find the derivative of f^1(4) if f(3)=4 and f'(3)=1/7 Answered by Penny Nom. 





Parallel lines 
20161026 

From Jordan: (7,5) 3x 4y=5 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. 





The volume of a hexagonal pyramid 
20161021 

From Elizabeth: Find the height of a hexagonal pyramid with a volume of 1320 ft ^3. The area of the base is 120 ft^2. Answered by Penny Nom. 





How many marbles does Haley have? 
20161019 

From Pat: Sabrina has 1/4 the marbles as Haley.
They have 305 total. How many marbles does Haley have? Answered by Penny Nom. 





A mixed number as a percent 
20161018 

From Jayda: how go you change a mixed number into a percent
Ex. 3 3/4 Answered by Penny Nom. 





y = mx + c and Ax + By + C = 0 
20161018 

From Erick: please explain to me how to convert an equation from the form y=mx+c to Ax+By+C=o form. Answered by Penny Nom. 





The degree of 2x + 7 
20161017 

From Deejay: How about when the given has no degree and the other has a constant only, For example 2x + 7,
where's the leading term and what is its leading coefficient? Answered by Penny Nom. 





Travelling upstream and downstream 
20161017 

From Kathleen: It took a boat 2 hours to reach town A going upstream. The way back was 1h20 min. What is the speed of the boat in still water if the speed of the stream is 3 mph? Answered by Penny Nom. 





A circle formed from bending a wire 
20161016 

From Deszaree: The same piece of a wire is bent to form a circle
calculate:
a, the radius of the circle
b, the area of the circle Answered by Penny Nom. 





A probability question concerning eggs 
20161016 

From Brian: Two participants are alternatively selecting eggs from a basket of 6 hardboiled eggs and 6 uncooked eggs.
Alternatively they are smashing the eggs on their foreheads. One participant gets 4 hard boiled eggs in a row and the other person gets 4 uncooked eggs in a row.
What is the probability of this occurring (I watched this happen).
Thank you
Brian Answered by Penny Nom. 





A linear relationship 
20161016 

From Bianca: x represents the number of hours since 8am. y represents the number of children the school nurse has seen during the school day. The nurse has seen 3 children by 8am and 27 children by noon.
How many children has the nurse seen at 2pm?
If the nurse has seen 18 children, what time is it? Answered by Penny Nom. 





An airplane schedule 
20161014 

From Stephanie: Starting at 8:00a.m., a passenger plane leaves from an airport every 6 minutes and a cargo plane leaves every 7 minutes. When is the next time these kinds of planes will leave at the same time? Answered by Penny Nom. 





Selina saved $6 on a 20% off sale 
20161014 

From Myra: I don't know how to help my child answer this question  Selina bought a shirt on sale that was 20% less than the original price. The original price was $6 more than the sale price. What was the original price? Answered by Penny Nom. 





A five digit number 
20161012 

From Massa: Explain why any four digit number is less than any five digit number? Answered by Penny Nom. 





Subtraction of two numbers in different bases 
20161007 

From Wica: Hello,
So happy I found this site. I am having problems with bases. My question is :
Please perform the subtraction between two number over different bases :
A. (5874)base 12  (216)base 9
B. (216)base 9  (5874)base 12 Answered by Penny Nom. 





How far is the boat from the harbour? 
20161006 

From Karabo: a boat sails 30 km due east from a harbour. Then it sails 40 km due north. How far is it from the harbour? Answered by Penny Nom. 





A kinky curve 
20161006 

From tammie: Koch’s kinky curve is created by starting with a straight segment and replacing it with four segments, each 1/3 as long as the original segment. So, at the second stage the curve has three bends. At the next stage, each segment is replaced by four segments, and so on. How many bends does the curve have at the third stage? Answered by Penny Nom. 





The remainder theorem 
20161004 

From A student: need help with this
f(x)=4x^415x^24; x2
using the remainder theorem to find the remainder Answered by Harley Weston. 





A triple product 
20161003 

From sam: Let a and b are vectors such that
Vector a = (1,1,2)
Vector b = (2,1,1)
And let vector c be a unit vector such that triple product of a,b,c is
minimum . We have to find the value of c.
[Thoughts]
I thought triple product of a b, c means the volume occupied by
parallelepiped. And we have to do volume minimum Answered by Penny Nom. 





The equation of a line 
20161001 

From Miriam: write the equation of the line that passes through (6,7) and is perpendicular to 3x+5y=0 Answered by Penny Nom. 





The equation of a circle 
20160930 

From Trent: write the equation of circle B with center B(2,3) that passes through (1,2) Answered by Penny Nom. 





Hexagonal pyramid bevel angles 
20160930 

From Peter: I have seen your response to a similar question from Steve which Chris and Harley responded to, however I am not familiar with some of the terms. Is there a formula that I can enter my details in which will give me the specific angles I require. The item I am constructing is much larger than the one you responded to previously. Thank you for any assistance you are able to provide. Answered by Penny Nom. 





Powers 
20160929 

From Ezra: i cant figure out this question. Can you please help
ezra
product of power (6x4)3 Answered by Penny Nom. 





A 2 million gallon tank 
20160928 

From Kimberly: I have a tank that is shaped like a cylinder, and it has to hold 2 million
gallons of water. There is a height limit of 30 ft.
I know the equation is V=pi x r squared x h but I don't know if I need anything
For the square foot of water. Answered by Penny Nom. 





Jenny, Charles and Chase have some butterflies 
20160926 

From Kyla: Jenny cares 7 times as many butterflies as Charles.
Charles catches 2 times as much as Chase.
All together they have 560 butterflies.
How many butterflies does each person have?
Please help, I am very confused on how to solve the problem.
Thank you! Answered by Penny Nom. 





A car chase 
20160925 

From Ms.: Car 1 is traveling down the road at 50 mph and passes Car 2 is
sitting on the side of the road. Car 2 needs to catch Car 1 one half mile
down the road. How fast must Car 2 drive to catch Car 1 if Car 2
waits 10 seconds before pursuing Car 1?
Yes, the assumption is that the Car 2 can accelerate from a standing position and over take Car 1 rate. What is the answer or formula for this type of question?
Respectfully
Befuddled Mom? Answered by Penny Nom. 





How fast and how far must Car 2 travel before catching Car 1? 
20160925 

From Ms.: Car 1 is traveling down the road at 50 mph and passes Car 2 is
sitting on the side of the road. Car 2 needs to catch Car 1 one half mile
down the road. How fast must Car 2 drive to catch Car 1 if Car 2
waits 10 seconds before pursuing Car 1?
Yes, the assumption is that the Car 2 can accelerate from a standing position and over take Car 1 rate. What is the answer or formula for this type of question?
Respectfully
Befuddled Mom? Answered by Penny Nom. 





2,0061234...484950 
20160924 

From Mimi: Compute the following:
2,0061234…484950 Answered by Penny Nom. 





The length of stock on a roll 
20160923 

From Ken: I have a roll that is 13.5 inches wide ( OD) , and is wound on a 3 inch core. the thickness of the material is 3.5 thick.
Do you know of a formula that can calculate the linear feet on that roll?? Answered by Harley Weston. 





Standard form 
20160922 

From anna: ok. i have b=2/3x+5/7. im supposed to change it to standard form. how do i do that? Answered by Penny Nom. 





The width of a 300 foot long rectangular acre 
20160921 

From Debbie: If 2 sides of a 1 acre plot is 300 feet each what are the other 2 sides? The acre is a rectangle. Answered by Penny Nom. 





The distance around a warehouse 
20160921 

From Chuck: How far do I walk when I walk around a 751,000 sq. ft. warehouse? Answered by Penny Nom. 





Two equations 
20160917 

From Nilesh: How to solve (xy)^1/2 + 3(xy) = 30 ; xy + 3(xy) = 11? Answered by Penny Nom. 





Integrate (x^2  4x + 4) ^4/3 
20160915 

From Ifah: Hi i have questions please answer
Integral 2 sampai 3 dari (x²  4x + 4) ^4/3 dx 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. 





Four digit numbers 
20160908 

From ning: 00009999 there is ten thousand 4digit numbers. How to find the number of ways that 4 digit are the same? How to prove it by using formula? Answered by Penny Nom. 





The equation of a ski slope 
20160831 

From Hannah: The information provided is
A ski slope has a slope of 0.2. You start at an altitude of 10,000ft.
Then the question is "Write the equation giving altitude (a) as a function of horizontal distance moved (d).
I know this is probably a very simple question but I didn't take a math class my senior year and now I'm a freshman in college, so some of it is very frustrating to me.
Any help is much appreciated, thank you! 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. 





Exponential form 
20160831 

From Lily: Hi! I was wondering, I was having a little issue understanding this one problem. It was "write 81 in exponential 2 different ways" and I already got 9(2) but I was wondering what the second one could be! Thanks! Lily Answered by Penny Nom. 





Todd Matt and Jeff 
20160830 

From Lisa: Three brothers spent different amounts of money on their recent vacation.
Matt spent $25 less than Todd.
Jeff spent 3 times as much as Matt.
How much did each brother spend if they spent a total of $275?
Check answer required
T= Todd Answered by Penny Nom. 





Two sequences 
20160820 

From Ting: The first four terms of a sequence are 4, 20, 56 and 120. By comparing with the nth term of sequence 1,5,14 and 30 which is 1/6n(n+1)(2n+1), find a formula for nth term. Can you precisely show out how you do this questions ( with the steps please) Answered by Penny Nom. 





I bought 3 books for $150.00 
20160820 

From Shavon: if i bought 3 books for $150.00 and 1 of the books cost 50% more than both other books combined what's the price of the more expensive book? 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. 





The ages of 10 children 
20160817 

From Diann: Sum total of the ages of 10 children 10 children is 110, what are their ages if all are 2 years apart?
thank you Answered by Penny Nom. 





5/8 of 16 
20160814 

From Michael: What is the fraction of 5/8 of 16 Answered by Penny Nom. 





A search area 
20160813 

From tammy: if your searching an area and you go 300 km from point A and search 380° what or how much area would you search? Answered by Penny Nom. 





Covering an octagonal region with sand 
20160813 

From Lynn: How much sand is needed to fill a 20 ft. wide octagon area 6 inches deep? Answered by Penny Nom. 





The area of a circle 
20160812 

From sandeep: if circumference of a circle is πd what is the area? Answered by Penny Nom. 





Five consecutive even integers 
20160812 

From Marcelle: The average of 5 even consecutive numbers is 112. What is the largest numbers? Answered by Penny Nom. 





A ship and a light 
20160811 

From Kirby: A ship is sailing due west when a light is observed with heading 297°50' from the ship. After the ship has travelled 2250 feet, the light heads 311°55' from the ship. If the course is continued, how close will the ship approach the light? Answered by Penny Nom. 





A 15% discount 
20160809 

From eunice: brian brought a printer sale at the store. the discount was 15%, and brian saved 550. what was the printer original price? 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. 





Carlos, Mark, Jeremy, and Alan collect Yugioh cards 
20160808 

From justin: Carlos, Mark, Jeremy, and Alan all collect Yugioh cards. Mark has twice as many cards as Jeremy. Carlos has 3 times as many cards as Jeremy, and Alan has collected 12 less than 3 times as many cards as Jeremy. Together the four players have collected 456 cards. How many does each person have? Answered by Penny Nom. 





Spraying an acre 
20160807 

From Sara: I have a spray rig that is 80' wide. How many feet must I go to have sprayed an acre? Answered by Penny Nom. 





A cone inscribed in a hemisphere 
20160807 

From anonymous: A cone is inscribed in a hemisphere. the slant height of the cone is 20cm. When cut along its slant height, the cone forms a sector of a circle.
find the angle of the sector, to the nearest 1 decimal place. Answered by Penny Nom. 





The diameter of a cylindrical tin 
20160804 

From Scott: a cylindrical tin is 15 inches high and holds 5 gallons of paint when it is full. Find the diameter of the tin.
(1 gallon = 0.1605 cubic feet) Answered by Penny Nom. 





The sequence 13 17 23 27 33 37 
20160729 

From Shriya: The first term of a sequence is 13.
The following terms are found by alternately adding 4 and 6 to the previous term.
The first six terms are 13 17 23 27 33 37.
Find the 80th term. Answered by Penny Nom. 





The modulus of a complex number 
20160729 

From Cheyenne: There's a question on my Summer Assignment I cant figure out. Here it is:
Find the absolute Value of the complex number. 5i
Please help? Answered by Penny Nom. 





The circumcentre of a triangle 
20160728 

From Raj: If the vertices of triangle ABC are A(4,1) B(1,2) C(4,3) then find coordinates of circumcentre of triangle 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. 





A cubic equation 
20160725 

From Chinmay: x³2x²7x+5 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. 





The temperature inside and outside a greenhouse 
20160722 

From Mehzad: Every day, the temperature in a greenhouse is at its low temperature, 70 degrees Fahrenheit, at 2 a.m. and at its high temperature, 84 degrees Fahrenheit, at 2pm. Its temperature increases linearly between 2 am and 2pm , and decreases linearly from 2 pm and to 2am. The outside temperature follows the same linear patterns, but has a low temperature of 60 degrees Fahrenheit at 2 am and a high temperature of 78 degrees Fahrenheit at 2 pm. At which of the following times will the temperature inside and outside the greenhouse be the same?
a) 8:00 am
b) 12:00 noon
c) 4:00 pm
d) The two temperatures will never be the same 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. 





Which term of this sequence has value 8? 
20160720 

From Lauren: Hi there
Which term in the sequence 2; 5/3; 4/3 ; 1; ... has a value of 8.
Since term 2 and 3 of this sequence contain fractions which can be converted to recurring decimals. What is the best way to work out the common difference here.
I do however understand that to work out the nth term of an arithmetic series, the following formula Tn = a + (n1)d. In this series a = 2 Answered by Penny Nom. 





Writing numbers in the form a/b 
20160717 

From Edward: How to write these numbers in form of a/b: 7, 0.175, 3.25, 37/10, 16, 1/3, 2.04 Answered by Penny Nom. 





A congruence theorem for two right angled triangles 
20160717 

From Sayari: Hello.
Is it possible for two right angled triangles to have the same length of base and height and a different hypotenuse? If not so, then why in the congruence criteria RHS the hypotenuse is given more importance? It can also be like 'two triangles are congruent if they are right angled and have the same base and height.'
Thank You. 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. 





If x+y=7 and x^2+y^2=42, then xy equals? 
20160717 

From Mehzad: If x+y=7 and x^2+y^2=42, then xy equals? Answered by Penny Nom. 





A train from Erie to New York 
20160714 

From carol: a train leaves Erie with twice as many women as men. At York, 17 men get on and 16 women . How many men and women were originally on the train?off. There are now the same number of men as women Answered by Penny Nom. 





Lisa went for a run 
20160714 

From Olive: Lisa ran 3km north and then 4 km east what was her total distance Answered by Penny Nom. 





The perimeter and area of a shape 
20160630 

From Scott: If I have a 16 x 32 rectangle the square feet is 512. So if I take a rope 96 feet long , which is the lineal feet of the rectangle, and manipulate it to any shape I want does the square footage inside the rope stay at 512 square feet? Thanks in advance! 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. 





Triakis 
20160627 

From Gordon: Some authorities treat "triakis" (and related terms "dyakis", "tetrakis", etc.) as attached prefixes; others treat them as separate adjectives. Thus I see one of the Catalan solids described as both "triakistetrahedron" and "triakis tetrahedron". Which usage is correct? Answered by Chris Fisher. 





Slope 
20160627 

From Ashiq: What is 1% slope if length 101 feet? Answered by Penny Nom. 





Subsets 
20160626 

From Kats: How Many sub sets are in set k={6,7,3} Answered by Penny Nom. 





find f+g 
20160626 

From yzabelle: find f+g
f(x)=x^21
g(x)=square root of x+2 Answered by Penny Nom. 





An equation involving pi 
20160626 

From Diaz: How would you solve :
( pie*X)/ 4 = pie/2
I have no idea.what to do! Answered by Penny Nom. 





Simultaneous equations 
20160625 

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





Sin squared (x) + Sin (x)  2 
20160625 

From Sree: Reduce the below to a single term
Sin squared (x) + Sin (x)  2
Thanks Answered by Penny Nom. 





An open ball is an open set? 
20160623 

From Aqeel: Theorem: The open ball is an open set? Answered by Harley Weston. 





Cubic feet of soil 
20160619 

From H: A garden is 8 ft x 7 ft that needs to raised 6 inch's How many cubic feet of soil required ? What am I missing ?
Thanks
H Answered by Penny Nom. 





Profit 
20160615 

From Toyia: 12.87 profit from 21.99 sale. What is the percentage that was taken off the 21.99 Answered by Penny Nom. 





Quadrilateral 
20160614 

From Muhib: Is there a quadrilateral with 0 sets of parallel sides. Answered by Penny Nom. 





A ratio of boys to girls 
20160612 

From Jasper: There are 600 pupils in a school. The ratio of the boys to girls in the school is 3:5 how many girls and how many boys are in the school Answered by Penny Nom. 





The difference between the ares of two rectangles 
20160609 

From Ingrid: I am trying to help my son with an area question.
I have the answer, from the solutions, but I cannot figure out how to teach him.
Question:
Two rectangles have lengths 13cm and 19cm respectively.
Their total area is 376cm squared.
If both their widths are whole numbers, what is the difference in their areas?
I know that this is solvable once I determine the widths of the rectangles ,
but how do I go about finding that?
Thanks for your help Answered by Chris Fisher and Harley Weston. 





Implicit differentiation 
20160606 

From Pranay: Is a circle x^2+y^2=2 a function? If it is not a function,
why is it possible to do implicit differentiation on it?
Thanks. 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. 





20 things taken 8 at a time 
20160530 

From Jessie: I need all of the 8 digit combinations using the numbers 120.
i.e 1 2 3 4 5 6 7 8, 2 3 4 5 6 7 8 9 like wise
no number should be repeated in one combination.
Thanks
Jessie Answered by Penny Nom. 





John and Max walk to meet each other 
20160529 

From abhay: The speeds of John and Max are 30 km/h and 40 km/h.Initially Max is at a place L and John is at a place M. The distance between L and M is 650 km. John started his journey 3 hours earlier than Max to meet each other. If they meet each other at a place P somewhere between L and M, then the distance between P and M is? Answered by Penny Nom. 





A barn roof 
20160529 

From Joe: Is it possible to build a barn roof (irregular pentagon?) with a 12' base and the other 4 sides 4' each? Thanks. Answered by Penny Nom. 





Placing a sphere in a cylinder of water 
20160527 

From Fiona: Hi the question i have is, if I have a cylinder filled with water and the volume of the water is 150Pi what would the rise in the level of the water be if you put a sphere into the cylinder with a volume of 500/3Pi? Sorry if it's a bit long winded Answered by Penny Nom. 





A cylinder in a cube 
20160525 

From Sonia: A cylinder has the same height and diameter as the sides of a cube use 3.14~ which has the greater volume 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. 





Two pieces of rope 
20160521 

From Render: Fred cuts a 12 inch piece of rope. Then he cuts a second piece of rope that is 3/2 longer than the first piece. Is the second piece shorter or longer than the first piece? Explain. 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. 





Euler's polyhedron formula 
20160520 

From Antonia: why does not cylinders follow Euler's polyhedron formula ( VE+F=2) ??
if a cylinder has 3 faces, 2 edges and 0 vertices it doesn't follow Euler's formula??? Answered by Penny Nom. 





The tens digit of a number is five times the unit digit 
20160519 

From sanjeev: The tens digit of a number is five times the unit digit. Find the number? Answered by Penny Nom. 





Filling a pit with glass pebbles 
20160517 

From Sam: I need to know how many pounds of glass pebbles are needed to fill a 24 inch across circular fire pit, if 5 pounds covers 4"H x 4"W x2"D? Thank u for any assistance, Sam Answered by Penny Nom. 





A puzzle embedded in a table top 
20160513 

From Aaron: I want to make a table with a puzzle embedded in it. The table top would be a
36" circle and the puzzle is 20"x27" I'm thinking that it's not going to fit,
but not sure. Any help would be appreciated.
Thanks,
Aaron 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. 





A 70% off sale< 