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Decimals and fractions |
2010-03-16 |
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From fay:
why do we use decimals in place of fractions in everyday life?
Answered by Robert Dawson. |
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A quadratic equation |
2010-03-15 |
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From rachelle:
under certain condition, it is found that the cost of operating an automobile as a
function of speed is approximated by a quadratic equation. use the data shown
below to find the function. then use the function to determine the cost of operating
the automobile at 60mph.
speed
(in miles per hour) |
operating cost
per mile(in cents) |
| 10 |
22 |
| 20 |
20 |
| 50 |
20 |
Answered by Penny Nom. |
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Gina's weight was 4/7 of Helen's weight |
2010-03-14 |
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From Eileen:
At first, Gina's weight was 4/7 of Helen's weight. Then, Gina gained 3kg while Helen lost 6kg. They are the same weight now. What is Helen's weight now?
Answered by Penny Nom. |
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Repeating Decimal |
2010-03-14 |
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From Gerald:
Find the 1987th digit in the decimal equivalent to 1785/9999 starting from decimal point. Can you give us a short but powerful technique in solving this problem? thanks so much..
Answered by Chris Fisher. |
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A red boat and a blue boat |
2010-03-13 |
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From SERENA:
Two fishing boats set out at 2pm for some afternoon fishing. Both boats pulled out from the same dock heading in the same direction. The average speed of the blue boat is 30mph slower then twice the speed of the red boat. In two hours, the blue boat is 20 miles ahead of the red boat. Find the rate of the blue boat.
Answered by Penny Nom. |
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Arc length and Chord length |
2010-03-13 |
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From Darryl:
Is there a formula to determine the chord length of an arc knowing only the arc length and the arc depth (sagitta)? I know you can't find the radius with only these two inputs, but can you find the chord length?
Answered by Harley Weston. |
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Constants and coefficients |
2010-03-12 |
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From lourdes:
identify the coefficients, constant term(s), and like terms of the expression.
8x + 9 - 3x
17 - 2a + 5a - 1
7m - 7 + 6m - 6
-10 -15r -22r + 8
Answered by Penny Nom. |
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The perimeter of a rectangle |
2010-03-12 |
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From makiah:
A rectangle has a perimeter of 12 meters.If each side is a whole number of meters,
what are the possible dimensions for the length and width?
Answered by Penny Nom. |
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A 14 side well house cover |
2010-03-12 |
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From Kenneth:
I am 35 yr I am wanting to build a well house cover. I'm trying to figure out how long the pieces need to be and what angle they need to be for a 4 ft dia with 14 side well house. I would love an answer but would also like to know how to figure it in the future. Thanks Kd
Answered by Harley Weston. |
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More on millions and billions |
2010-03-11 |
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From julio:
shouldn't the thousands of millions, tens of thousands of millions, and hundreds of thousands of millions be called what they are? technically they are not billions because billions come after 999,999,999,999 . It would sound better to call the numbers by their real name when economists talk about the national deficit besides mathematics is a very precise science that doesn't admit mistakes. Or am I wrong? I know that in other countries is expressed different than here. I have this question to different people and nobody has a "logical" explanation to it. " that's the way is here in the US" does not explain any thing
Answered by Penny Nom. |
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Selling lettuce |
2010-03-11 |
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From Mike:
Day 1 started with 80 heads of lettuce and x were sold.
Day 2 started with two times the number of heads of lettuce that was left
over. Again, only x were sold.
Day 3 started with 3 times the number
of lettuce from what was left over from day 2 and all was sold.
What
was the # of lettuce sold on each day?
Answered by Penny Nom. |
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Division |
2010-03-10 |
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From lucas:
bonjour je suis eleve de 6 eme
je bloque sur ce petit probleme
Nat a fait une division,elle ecrit
4568=23*198,608+reste
que vaut ce reste?
merci d'avance
lucas
Answered by Claude Tardif. |
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I want to add 4.3% |
2010-03-10 |
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From Brandy:
I am trying to find out a total. I have 7,118.00 and I want to add 4.3% to that total. How do I do that.
Answered by Penny Nom. |
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The nth derivative of x^(n-1) log x |
2010-03-10 |
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From shambodeb:
This is a successive differentiation problem by Leibnitz theorem
If y = xn-1 log x ; Proof nth derivative y(n) = (n-1)!/x
Answered by Harley Weston. |
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A 6m ladder is placed against a wall |
2010-03-09 |
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From Trevor:
A 6m ladder is placed against a wall making a 56 degree angle with the ground. How far up the wall does the ladder reach?
Answered by Harley Weston. |
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