Last Updated on May 11, 2023
GMAT Guide
Solution:
We can write the question:
Is xy/(x + y) = integer?
Statement One Alone:
x = y
Since x = y, we have:
Is xy/(x + y) = integer?
Is (x)(x)/(x + x) = integer?
Is x^2/2x = integer?
Is x/2 = integer?
Since we don’t have a value of x, we cannot determine whether x/2 is an integer. For example, if x = 2, then x/2 is an integer; however, if x = 3, then x/2 is not an integer. Statement one alone is not sufficient to answer the question.
Statement Two Alone:
x = 2
Only knowing that x = 2 is not enough to determine whether xy/(x + y) = integer. Statement two alone is not sufficient to answer the question.
Statements One and Two Together:
Using the statements together, we see that since x is 2, we can say that 2/2 = 1, which is an integer.
Answer: C
