For how many positive integers n such that 7n+1 is divisible by 3n+5?
If n = 1, (7n + 1)/(3n + 5) = 1
If n = 9, (7n + 1)/(3n + 5) = 2.
The quotient (7n + 1)/(3n + 5) can never reach 3 because, as n approaches infinity,
the lim (7n + 1)/(3n + 5) = 7/3.
There are only two possibilities.
