Data Sufficiency

Hey guys, another DS question please (i hate DS :p)

What is the greatest common divisor of positive integers m and n?

1. m is a prime number
2. 2n = 7m

1 alone is insufficient as it says nothing about n
2 alone is insufficient because multiple values of m and n work, such as 10 and 35 (gcd = 5), 4 and 14 (gcd = 2), etc. etc.

If both are taken together, then since m is a prime number, for 7m = an even number (i.e. 2n), m = 2. If m = 2, then 2n = 14, n = 7. Therefore the gcd = 1.

Does this make sense? Or am I missing something?

I don't find anything wrong with your approach. This is the way the question is to be attacked!


What's the OA??

thanks very much! the OA is C, both