Hi All,

This DS question can be solved by TESTing VALUES (although recognizing the built-in Number Properties would help make solving this problem easier).

We're told that WXY is not = 0, so NONE of those variables can = 0. We're asked if X = Y. This is a YES/NO question.

To start, it's interesting that this prompt has 3 variables, but the question focuses on just 2 of them. That almost always means that the third variable (in this case, the W) will play a role in defining the other two variables.

Fact 1: W^X = W^Y

Since the 'base' on both sides of this equation are Ws, it might be tempting to think that this X = Y. However, you have to be thorough with your thinking....

IF...

W = 2

X = 3

Y = 3

2^3 = 2^3 and the answer to the question is YES.

But what happens if W = 1 or W = -1? Do the exponents even matter at that point?

IF...

W = 1

X = 1

Y = 5

1^1 = 1^5 and the answer to the question is NO.

Fact 1 is INSUFFICIENT

Fact 2: WXY is NOT = XY

This pinpoints one specific restriction about W....W CANNOT = 1. Unfortunately, it doesn't tell us anything about X and Y

IF....

W =2

X = 1

Y = 1

The answer to the questions is YES.

IF...

W = 2

X = 1

Y = 3

The answer to the question is NO.

Fact 2 is INSUFFICIENT

Combined, we know...

W^X = W^Y

W CANNOT = 1

IF....

W = 2

X = 3

Y = 3

2^3 = 2^3 and the answer to the question is YES.

IF....

W = -1

X = 1

Y = 3

(-1)^1 = (-1)^3 and the answer to the question is NO.

Combined, INSUFFICIENT.

Final Answer:

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

Rich

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