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by resilient » Mon May 26, 2008 4:39 pm
A 10-by-6 inch piece of paper is used to form the lateral surface of a cylinder. If the entire piece of paper is used to make the cylinder, which of the following must be true of the two possible cylinders that can be formed?


a.The volume of the cylinder with height 10 is 60/ cubic inches greater than the volume of the cylinder with height 6.


b.The volume of the cylinder with height 6 is 60/ cubic inches greater than the volume of the cylinder with height 10.


c.The volume of the cylinder with height 10 is 60 cubic inches greater than the volume of the cylinder with height 6.


d.The volume of the cylinder with height 6 is 60 cubic inches greater than the volume of the cylinder with height 10.


e.The volume of the cylinder with height 6 is 240/ cubic inches greater than the volume of the cylinder with height 10.


qa is


b


what is wrong with d?
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Source: — Problem Solving |

by aatech » Mon May 26, 2008 6:17 pm
ANS B- Assuming "60/" in the sentence stands for "60/pi" actially

Volume of cylinder is pi*r^2*h

Case 1 - Height 6, so base perimeter = 10 = 2*pi*r => r = 5/pi

Volume 1 = Put the values in the volume formula above = 150/pi

Similarly for case 2 (Height 10) - volume = 90/pi

Diff = 60/pi

Please confirm if my assumption above is right.
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MGMAT

by resilient » Mon May 26, 2008 6:51 pm
THat is all the information that is given to me.

I still am not understand the difference and why that d is wrong. I am still stuck between d and b.
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by aatech » Mon May 26, 2008 6:54 pm
What is the source of the question... ???

I have a good gut feeling that b is saying "60/pi" and d is saying only "60"... that's the diff between b and d
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mgmat

by resilient » Mon May 26, 2008 7:12 pm
this question comes from mgmat. Can you see where the confusion comes from. Im not fully convinced.
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by aatech » Tue May 27, 2008 5:17 am
I am saying so as there is "/" along with 60 in the choices a and b... "60/" does not make sense.. that's why I am saying 60/pi
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lost the sign in the process

by resilient » Tue May 27, 2008 6:02 am
A 10-by-6 inch piece of paper is used to form the lateral surface of a cylinder. If the entire piece of paper is used to make the cylinder, which of the following must be true of the two possible cylinders that can be formed?


The volume of the cylinder with height 10 is 60/3.14 cubic inches greater than the volume of the cylinder with height 6.


The volume of the cylinder with height 6 is 60/3.14 cubic inches greater than the volume of the cylinder with height 10.


The volume of the cylinder with height 10 is 60(3.14) cubic inches greater than the volume of the cylinder with height 6.


The volume of the cylinder with height 6 is 60(3.14) cubic inches greater than the volume of the cylinder with height 10.


The volume of the cylinder with height 6 is 240/(3.14) cubic inches greater than the volume of the cylinder with height 10.
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