Answer
To satisfy the conditions, the annual interest rate must be 22%.
Work Step by Step
Compounding Interest = $Pe^{rt}$ where $P$ is the Principal, $r$ is the annual interest rate and $t$ is the time in years. Since we're asked to find $r$ when $t = 5$ and the principal has tripled: $$3P = Pe^{r(5)}$$ $$3 = e^{5r}$$ $$5r = \ln 3$$ $$r = \frac{\ln 3}{5} \approx 0.22$$
