## Precalculus (6th Edition) Blitzer

$22 \%$
The formula for continuously compounded interest is given by : $A= Pe^{rt}$ Plug in the given data. $3x=(x) e^{5r}$ or, $3 =e^{5r}$ Take the natural log of each side. $\ln 3 =5r \implies r= \dfrac{\ln 3}{5} \approx 0.2197 \approx 22 \%$