Hotline tư vấn: 028.7108 8558 (TP.HCM) / 024.7106 5888 (Hà Nội) / 098 111 3529

# GMAT Question of the Day – 11/01/2021

### QUESTION

What is the value of a ?

STATEMENT 1:

a 2 = b2

STATEMENT 2:

b a = -12

Statement (1): insufficient. All we know is that the square of a equals the square of b. a can have any real value. Thus, we can have a = 3 and b = 3. We can have a = 7 and b = 7. Let’s note that we must have a = b or a = –b. So a and bdo not have to be equal. a can be the negative of b. Since a can have any real value, statement (1) is insufficient. We can thus eliminate choices (A) and (D).

Statement (2): insufficient. Solving for a, we have that a = b + 12. However, since we have no value for b, it is impossible to determine the value for a. Eliminate choice (B).

Statements (1) and (2): sufficient. We know from statement (1) that a = b or that –a = b. Looking at statement (2), we know that it must be the latter, for a cannot equal a + 12. So, substitute –a for b in the equation b a = -12. Then -a – a = -12, or -2a = -12. Thus, we can find the value of a. The statements taken together are sufficient. Choice (C) is correct.

Tags: