can some one explain?

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can some one explain?

by swapna » Wed Feb 03, 2010 10:49 am
If s and t are positive integers such that s/t = 64.12,which of the following could be the remainder when s is divisible by t?

a.2
b.4
c.8
d.20
e.45

ans is e. The question is from official guide 11th edition.dint really follow the explanation.can some one exp
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by Osirus@VeritasPrep » Wed Feb 03, 2010 10:52 am
with the result being 64.12, what you would want to do is reduce the fraction 12/100. The reduced fraction would be 3/25. With the answer choices you want to look for any answer that is above 3 and also a multiple of 3. Only 45 satisfies this criteria.

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can some one further elaborate?

by swapna » Wed Feb 03, 2010 10:59 am
thanks...but am still nt gettin it....can u further elaborate?i understood till the reduced fraction part...not after that...

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by Osirus@VeritasPrep » Wed Feb 03, 2010 11:04 am
swapna wrote:thanks...but am still nt gettin it....can u further elaborate?
Sure

The remainder has to be smaller than the divisor. The remainder is the non integer part of the answer. So in the number 64.12. The remainder is the .12

to find what the actual remainder could be, you would need to first make the .12 into a fraction. To make it into a fraction you would would simply put the number over 100 or 12/100. You reduce this and you get 3/25. Since this is the fraction we know that the lowest the remainder could be is 3. However, since we don't know the value of the divisor there is no upper limit on the remainder. Therefore, all we know is that the remainder will be a multiple of 3. The remainder could be 3, 6, 9, 12, 15, etc. Without knowledge of the divisor, all we know is that the remainder is a multiple of 3. When you see a question like this, approach it like I outlined and you will be fine.

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by Ian Stewart » Wed Feb 03, 2010 1:02 pm
I gave a solution to this problem here:

www.beatthegmat.com/difficult-t15709.html

You may wish to see my comment at the end about the difficulty level of the problem.
For online GMAT math tutoring, or to buy my higher-level Quant books and problem sets, contact me at ianstewartgmat at gmail.com

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