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
Hi Rich. Would be great if you can elaborate on the highlighted text - How did you deduce that conclusion?
Cheers. Wishing Luck to Every GMAT Aspirant | Press +1 if this post helped you!