Is x > y ?

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Is x > y ?

by Manonamission » Tue Oct 11, 2016 6:58 am

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If x and y are integers, is x > y?

(1) x + y > 0
(2) y^x < 0

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by [email protected] » Tue Oct 11, 2016 9:40 am

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Hi Manonamission,

This question can be solved by TESTing VALUES (and knowing your Exponent rules would help).

We're told that X and Y are INTEGERS. We're asked if X is greater than Y. This is a YES/NO question.

1) X+Y > 0

IF... X=2, Y=1 then the answer to the question is YES.
IF... X=1, Y=2 then the answer to the question is NO.
Fact 1 is INSUFFICIENT

2) Y^X < 0

For this value to be LESS than 0, the X cannot be an even integer. As such, X could be a positive or negative odd number. The Y MUST be negative though (since a negative raised to an odd power will end in a negative).

IF... X= 1, Y= -1 then the answer to the question is YES.
IF... X= -1, Y= -1 then the answer to the question is NO.
Fact 2 is INSUFFICIENT

Combined, we know...
X+Y > 0
X is odd
Y is negative

Since Y has to be NEGATIVE and (X+Y) > 0, then the X MUST be POSITIVE. By extension, the answer to the question is ALWAYS YES.
Combined, SUFFICIENT

Final Answer: C

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