The local government projects that the town will grow at a constant rate of thirty-two percent per year. At this rate, how many years will it take the town's population to be five times its current size?

You want to find n such that
  (1.32)^n = 5
Such an equation is solved using logarithms.   n*log(1.32) = log(5)
  n = log(5)/log(1.32)
  n ≈ 5.797
It will take nearly 6 years for the population to grow to 5 times its current value.