As n ranges over the positive integers, what is the sum of all possible values of the greatest common divisor of 3n+4 and n?
If we start listing out the gcds, you'll notice that they repeat, 1, 2, 1, 4.
I'm pretty sure this is due to the +4 in 3n + 4.
So the possible values are 1, 2, and 4.
1 + 2 + 4 = 7
I hope this helped. :)))