prashanths
Is \(\sqrt{\sqrt[n]{m}}\) an integer?
(1) m = n + 14
(2) m = 5n + 6
Interesting problem! Here's how I approached it:
First, I noticed that both statements together would definitely allow me to answer the question. That's because both statements together will give you the values of m and n, and that would let you calculate the exact answer, if you really wanted to. Here's what that made me think: uh-oh, this might be a C trap. I'm going to try very carefully to prove that each statement alone is insufficient before I assume the answer is C.
Then, I rewrote the question to look a little clearer:
Is \(m^\frac{1}{2n}\) an integer?
Statement 1: Let's start writing out cases and see if we can find some integers and non-integers.
First case: n = 1, m = 15. Is \(15^\frac{1}{2}\) an integer? NO.
Second case: n = 2, m = 16. Is \(16^\frac{1}{4}\) an integer? YES, and its value is 2.
The answer can be either YES or NO, so this statement is insufficient. Eliminate A and D.
Statement 2: Let's write out some more cases.
First case: If n = 1, m = 5(1) + 6 = 11. Is Is \(11^\frac{1}{2}\) an integer? NO.
Second case: n = 2, m = 16. Is \(16^\frac{1}{4}\) an integer? YES, and its value is 2.
The answer can be either YES or NO, so this statement is insufficient. Eliminate B.
Statements together: We can solve and find that m = 16, n = 2, and the answer is definitely YES. That's why the answer is C.