Answer to GMAT Question #12

Here is the answer to GMAT Practice Question #12

Answer: C

Explanation:
Rewrite the question as:

See Image 1

Using the information in Statement (1), we determine that:

x + y = x - z
y = -z

Since y is the negative of z, their sum would be zero, but since we do not know what x is, we cannot determine the average. Therefore, this information alone is insufficient.

The information in Statement (2) alone does not help us because we do not know what y and z are.

If we combine the information in the two statements, we have:

See Image 2

Which enables us to answer the question.

The answer and explanation to GMAT Practice Question #12 was written by Integrated Learning, a company that provides professional and private one on one tutoring services.