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Small pipes and large pipes |
2006-05-09 |
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From geece:
A large fresh water reservoir has two types of drainage system. Small pipes and large pipes. 6 large pipes, on their own, can drain the reservoir in 12 hours. 3 large pipes and 9 small pipes, at the same time, can drain the reservoir in 8 hours.
How long will 5 small pipes, on their own, take to drain the reservoir?
Answered by Penny Nom. |
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Coconuts and Monkeys |
2006-05-08 |
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From Meadow:
5 sailors plan to divide a pile of coconuts among themselves in the morning. During the night, one of them decides to take his share. After throwing a coconut to a monkey to make the division come out even he takes 1/5 of the pile. The other four sailors repeat this procedure, each throwing a coconut to the monkey and taking 1/5 of the remaining coconuts. In the morning the 5 sailors throw a coconut to the monkey, and divide the remaining coconuts into 5 equal piles. What is the minimum number of coconuts that could have been in the pile originally?
Answered by Paul Betts. |
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Twenty golfers |
2006-05-08 |
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From Mona:
We have twenty golfers and four rounds of golf. We would like to figure out how to make foursomes so that each golfer plays with as many different golfers as possible.
Answered by Penny Nom. |
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The square root of 4 |
2006-05-07 |
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From MaryBeth:
I am a high school teacher of Algebra. I was recently teaching square roots to my students and an interesting question arose. Our textbook seems to be inconsistent. I was hoping you might be able to give our department your opinion on who is correct as we are divided on the correct way to teach this. When you take the square root of a number, you get two answers, a positive root and a negative root, correct? Our book presents this as √4 = 2 and -√4 = -2 and ±√4 = ±2. Shouldn't it be taught as there are always two roots, the positive and the negative? It seems to me, there is really no reason to have to use the ± as there are always 2 roots, the positive and the negative. But if the negative sign is given then only the negative answer should be given? What's your take?
Answered by Penny Nom. |
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Cutting an octagon from a square |
2006-05-07 |
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From Veronica:
1.A regular octagon is to be cut out of a square piece of metal which has sides of 1 metre. What will be the length of the sides of the octagon?
2.What will be the area of the octagon?
Answered by Penny Nom. |
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Round to the nearest tenth |
2006-05-06 |
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From Lisa:
how to round a decimal fraction to the nearest tenth
Answered by Penny Nom. |
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A hallway in an old house |
2006-05-06 |
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From Sabrina:
I am trying to determine how many square feet is in a room that is not square or rectangular. It has basically 5 walls of different lengths, it is acutely considered a hallway in an old house, how can I figure out the footage, the Length times Width requires to much wasted materials
Answered by Penny Nom. |
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A number theory problem |
2006-05-05 |
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From DeHayward:
Find the 6-digit number in which the first digit is one less than the second, the third is half of the second, the fourth is 3 times the third, and the last 2 digits are the sum of the fourth and fifth. The sum of all the digits is 24.
Answered by Paul Betts. |
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More on the game of 24 |
2006-05-05 |
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From Kathy's daughter:
My daughter's 5th grade class plays the 24 math game. She came home
the other day with a real stumper! The numbers on the card are 5,5,2,and 6.
The rules say you must use every number,you may only use a number once,you
can only add, subtract, multiply and/or divide and the answer is 24. Can you
help!!!! No one where I work has been able to figure this one.
Answered by Paul Betts and Penny Nom. |
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The radius of a soccor ball |
2006-05-05 |
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From Jacqui:
A soccer ball is made up of hexagons and pentagons with the same side lengths.
A manufacturer wants to produce a ball of certain diameter. The questions that follows is what side length for the polygons will produce a ball of certain diameter.
Answered by Chris Fisher. |
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5 square miles or a 5-mile square? |
2006-05-03 |
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From Rosemary:
I am an interpreter in our Historical Museum. From what I received, I have always told my guests that when the Connecticut Land Company sold the Western Reserve land, 5 square miles constituted a township. I was corrected yesterday by someone who said it should have been a 5-mile square. What is the difference? Hope you can help.
Answered by Penny Nom. |
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Cutting a piece of PVC pipe |
2006-05-03 |
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From Shonda:
A plumber has a 10' piece of PVC pipe. How many 9/5 foot pieces can be cut from the 10' piece?
Answered by Penny Nom. |
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A fountain of water jets forms parabolic arches |
2006-05-03 |
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From Jennifer:
Let's say in you have a fountain and the water jets form parabolic arches. The center of the fountain, being the origin of the coordinate system, it is elevated 5 feet off the ground, . The equation formed the water arch is y= -x2+4x, what is the radius of the basin needed to catch the water at ground level?
Answered by Stephen La Rocque. |
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A parabolic arch |
2006-05-02 |
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From Mike:
A bridge over a river is supported by a parabolic arch...arch is 200 m wide at water level...the maximum height of the arch is 80 m..what is the height of the arch measured from a point on the water 40m from the center of the arch?
Answered by Stephen La Rocque. |
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A limit involving trigonometry |
2006-05-02 |
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From Allie:
My question is how do you solve.
lim as t goes to 0 [sin squared *3t] / t squared?
Answered by Penny Nom. |
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