Hi M7MBA,

We're asked if (P)(Q) > 1. This is a YES/NO question. We can solve it by TESTing VALUES and/or by using Number Property Rules.

1) P^Q = 1

With the equation in Fact 1, we know that one of the following must be occurring:
A) P = 1 and Q is ANY value
B) P = ANY value and Q = 0

With the first example, the product (P)(Q) could be greater than 1 (a YES answer), equal to 1 (a NO answer) or less than 1 (also a NO answer).
With the second example, the product (P)(Q) will always be 0, so the answer to the question is NO.
Fact 1 is INSUFFICIENT.

2) Q = -1

Fact 2 tells us nothing about the value of P, so there's no way to answer the question.
Fact 2 is INSUFFICIENT.

Combined, we know...
P^Q = 1
Q = -1
So (P)^(-1) = 1. The only solution to this equation is P=1, so (1)(-1) = -1 and the answer to the question is ALWAYS NO.
Combined, SUFFICIENT.

Final Answer: C

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