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
GMAT assassins aren't born, they're made,
Rich
