Scott Woodbury-Stewart

GMAT OFFICIAL GUIDE DS – If n + k = m…

If n + k = m…

Solution:

We are given that n + k = m, and we need to determine the value of k. Since we know that n + k = m, we know that k = m – n. Thus, if we determine a value for m – n, we will know the value of k.

Statement One Alone:

n = 10

Although we know that n = 10, without knowing the value of m, we cannot determine the value of k. Statement one alone is not sufficient. We can eliminate answer choices A and D.

Statement Two Alone:

m + 10 = n

Manipulating statement two we get:

m + 10 = n

m – n = -10

Since we know that m – n = -10, we know that k = -10. Statement two alone is sufficient.

Answer: B