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Need help with this data sufficiency problem

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by vijayrr007 » Sun Feb 26, 2012 9:15 am
I think the answer is A. we get 2x=3y from 1 which means the ratio is 3:1. for 2 since its a square we are not sure whether its positive or negative. it can be 2x=3y or -2x=3y.
targetthegmat wrote:If x and y are integers, what is the ratio of 2x to y?
8x3 = 27y3 (read x cube, y cube)
4x2 = 9y2 (read x square, y square)
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by pemdas » Sun Feb 26, 2012 6:28 pm
targetthegmat wrote:If x and y are integers, what is the ratio of 2x to y?
8x3 = 27y3 (read x cube, y cube)
4x2 = 9y2 (read x square, y square)
2x/y?
st(1) 8x^3=27y^3 implies (2x)^3=(3y)^3 or 2x=3y which is Sufficient to answer 2x/y, as 2x/3y=1 and 3*(2x/3y)=3

st(2) 4x^2=9y^2 implies (2x)^2=(3y)^2 or |2x|=|3y| Not Sufficient

a
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by Anurag@Gurome » Mon Feb 27, 2012 2:21 am
targetthegmat wrote:If x and y are integers, what is the ratio of 2x to y?
8x3 = 27y3 (read x cube, y cube)
4x2 = 9y2 (read x square, y square)
(1) 8x^3 = 27y^3
(2x)^3 = (3y)^3
Taking cube root on both sides,
2x = 3y
2x : y = 3 : 1; SUFFICIENT.

(2) 4x² = 9y²
Taking square root on both sides,
±2x = 3y; NOT sufficient.

The correct answer is A.
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by spideygirl » Sat Apr 27, 2013 12:34 pm
Hi, I have a question. I had picked (E) because I took the scenario of x and y being set to 0. Is it incorrect to use 0 as a value to plug in for x and y? Can we not take zero for both because x and y are two different variables?
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