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DS - numbers

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DS - numbers

by oks » Wed May 13, 2009 5:01 pm
If X3Y = 24, what is the value of (X3Y3 – X2Y2)?
(1) X2Y2 = 36.
(2) X3Y2 = 72.

I thought the answer is D, but it's not correct. Thoughts?

OA: B
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Source: — Data Sufficiency |
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by DeepakR » Wed May 13, 2009 5:40 pm
From #1 we can only find x/y i.e.
x^2y^2=36 and x^3y=24 hence dividing we get, x/y=24/36
so its insufficient.

From #2 we have x^3*y^2=72 and substituting x^3*y=24 in the above equation we get x=2 and y=3 with which we can find x^3*y^3-x^2*y^2
so B.) alone is sufficient.

- Deepak
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