## GMAT Prep Practice Test Quant Questions #4

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### GMAT Prep Practice Test Quant Questions #4

by simpm14 » Tue Apr 09, 2019 8:33 am
If wx = y, what is the value of xy ?

(1) wx2 = 16
(2) y = 4

Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.

Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.

BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.

EACH statement ALONE is sufficient.

Statements (1) and (2) TOGETHER are NOT sufficient.

Answer is A. Cannot figure out why.

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by [email protected] » Tue Apr 09, 2019 8:43 am
simpm14 wrote:If wx = y, what is the value of xy ?

(1) wxÂ²= 16
(2) y = 4
Given: wx = y

Target question: What is the value of xy ?

Statement 1: wxÂ²= 16
We can rewrite this as: (wx)(x) = 16
Since wx = y, we can replace wx with y to get: (y)(x) = 16
So, the answer to the target question is xy = 16
Since we can answer the target question with certainty, statement 1 is SUFFICIENT

Statement 2: y = 4
There are several values of w, x and y that satisfy statement 2. Here are two:
Case a: w = 1, x = 4 and y = 4. In this case, the answer to the target question is xy = 16
Case b: w = 2, x = 2 and y = 4. In this case, the answer to the target question is xy = 8
Since we cannot answer the target question with certainty, statement 2 is NOT SUFFICIENT

Answer: A

Cheers,
Brent

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