Is X an integer if AB > 0?
1. X = 2A - 5B
2. A = B
A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
D. EACH statement ALONE is sufficient.
E. Statements (1) and (2) TOGETHER are NOT sufficient.
Answer
If A and B are both integers then 2A and 5yB are integers and thus X is an integer.
If they are not integers, however, we have no guarantee that 2A - 5B will be an integer.
Statement 1 is insufficient. Statement 2 tells us that A = B. Because this tells us nothing about X, Statement 2 is insufficient.
If we take Statements 1 and 2 together, we still can't determine if X is an integer because we do not know the value of A. 21.
Correct Answer - Choice E