Data Sufficiency

alanforde800Maximus wrote:What is the median of set A {-8, 15, -9, 4, N}?

1) N is a prime and N� is even

2) 2N + 14 < 20

Please assist with above problem.

Target question: What is the median of set A

Given: set A {-8, 15, -9, 4, N}

Statement 1: N is a prime and N� is even
- If N is even, then N� is even
- If N is odd, then N� is odd
Since we're told that N� is even, we can conclude that N is EVEN, which means N = 2 (since 2 is the only even prime)
Once we know N = 2, set A becomes {-8, 15, -9, 4, 2}, in which case, the median of set A is 2
Since we can answer the target question with certainty, statement 1 is SUFFICIENT

Statement 2: 2N + 14 < 20
Subtract 14 from both sides of the inequality to get; 2N < 6
Divide both sides by 2 to get: N < 3
There are several values of N that satisfy statement 2. Here are two:
Case a: N = 2, in which case set A becomes {-8, 15, -9, 4, 2}. In this case, the median of set A is 2
Case b: N = -10, in which case set A becomes {-8, 15, -9, 4, -10}. In this case, the median of set A is -8
Since we cannot answer the target question with certainty, statement 2 is NOT SUFFICIENT

Answer = A

Related video: https://www.gmatprepnow.com/module/gmat ... /video/800

Cheers,
Brent