is x>y ?

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is x>y ?

by asciijai » Mon Nov 30, 2015 2:53 am
If |3x| > |4y|, is x > y?

(1) x > 0

(2) y > 0

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by GMATGuruNY » Mon Nov 30, 2015 3:29 am
asciijai wrote:If |3x| > |4y|, is x > y?

(1) x > 0

(2) y > 0
Rephrase |3x| > |4y| so that one of the variables is IN TERMS OF THE OTHER:

3|x| > 4|y|
Thus:
|y| < (3/4)|x|
and
|x| > (4/3)|y|

Statement 1: x > 0
Substituting positive values for x into |y| < (3/4)|x|, we get:
If x = 4, then |y| < 3, with the result that x > y.
If x = 1/2, then |y| < 3/8, with the result that x > y.
If x = 40, then |y| < 30, with the result that x > y.
In every case, x > y.
SUFFICIENT.

Statement 2: y > 0
Substituting y=3 into |x| > (4/3)|y|, we get:
|x| > 4.
Here, it's possible that x=5 and y=3 (with the result that x>y) or that x=-5 and y=3 (with the result that x<y).
INSUFFICIENT.

The correct answer is A.
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by GMATinsight » Wed Dec 02, 2015 7:35 am
asciijai wrote:If |3x| > |4y|, is x > y?

(1) x > 0

(2) y > 0
Since, |3x| > |4y|

therefore, |x| > |4y/3|

therefore, |x| > |1.33y|

Statement 1: x > 0
If x is positive then whether y is Negative or positive x will always be greater than y. Hence,
SUFFICIENT

Statement 2: y > 0
Since sign of y is unknown so x may be greater than y for positive value of x or x may be smaller than y for negative value of x
e.g. @y=1
x may be +2 or -2
NOT SUFFICIENT

Answer: option A
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