Easy.

Both circumferences have the factors 2 x pi in them, so that is not necessary to consider in a proportional ratio. (Cross out common denominators).

Given that a circumference = 2 x pi x r, the only proportions we need to worry about are the radii.

The ratio of the radii is 3:1. Therefore the circumferences will be 3:1. The first circle needs to go round the bigger circle 3 times.

Note there is a trap, in the answer that is 9. This is for people who confuse 2 x pi x r for pi x r-squared (to give Area), which would result in 3 x 3 = 9.

Edit: Ooops I did not see your request to not comment if you knew the answer.