Hi All,
We're asked for the value of 2X/3Y. This question can be solved by TESTing VALUES.
1) (X^2)/(Y^2) = 36/25
IF....
X=6, Y=5, then the answer to the question is 12/15 = 4/5
X=6, Y= -5, then the answer to the question is 12/-15 = -4/5
Fact 1 is INSUFFICIENT
2) X^5/Y^5 > 1
With this inequality, we know that X and Y must be the SAME sign (either both positive or both negative).
IF....
X=6, Y=5, then the answer to the question is 12/15 = 4/5
X=6, Y=1, then the answer to the question is 12/3 = 4
Fact 2 is INSUFFICIENT
Combined, we know...
(X^2)/(Y^2) = 36/25
X^5/Y^5 > 1
Since X and Y must be the SAME sign, we have two immediate examples that 'fit' both Facts....
IF....
X=6, Y=5, then the answer to the question is 12/15 = 4/5
X= -6, Y= -5, then the answer to the question is -12/-15 = 4/5
X and Y could be other values though, but the only pairs of values that fit the first equation will be in the ratio of 6:5. For example....
IF....
X=12, Y=10, then the answer to the question is 24/30 = 4/5
X= -12, Y= -10, then the answer to the question is -24/-30 = 4/5
The answer will ALWAYS be 4/5.
Combined, SUFFICIENT
Final Answer: C
GMAT assassins aren't born, they're made,
Rich
