Jeff Miller

GMAT OFFICIAL GUIDE DS – What is the value of…

What is the value of…

Solution:

We need to determine the value of integer n.

Statement One Alone: 

n(n+1) = 6

Let’s solve the equation:

n(n+1) = 6

n^2 + n = 6

n^2 + n – 6 = 0

(n+3)(n-2) = 0

n = -3 or n =2

Since we have two values for n, statement one alone is not sufficient. We can eliminate answer choices A and D.

Statement Two Alone: 

2^(2n) = 16

We express 16 as a power of 2, and then we equate the exponents; we can then determine a value for n.

2^(2n) = 2^4

2n = 4

n = 2

Statement two is sufficient to answer the question.

Answer: B

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