What exactly am I being asked in this question? I don't need the answer, just the interpretation. 
Write a program that inputs a whole number N and outputs the percentage of relatively prime pairs of numbers a, b in the range 1 to N. 

For some reason, I'm having difficulty understanding the question. Do I need to calculate the probability of a and b being co-primes? Do I need to find the gcd? I’m not sure what I'm being asked.
Also, please provide an end answer or an example, so that I have something to check my answer against and know that I'm on the right track. Thank you.

You could compute $\sum_{n=1}^N \phi(n)$, which would be $O(N log N)$, to find the number of coprime pairs $1 \leq a<b\leq N$.
