If you invest in an account that earns 4.5% interest compounded continuously..

Question

If you invest in an account that earns 4.5% interest compounded continuously, how long will it take to triple your money assumig you leave it in the account?

Just another fun question from a website :D

Answer 1

$$A = Pe^{rt}$$

You didn't specify any time unit on the rate, so I will assume it is 4.5% annual interest rate compounded continuously.

Then we have $r = 0.045$ and we are interested in solving for $t$ when $A = 3P$.

$$3P = Pe^{0.045t} \Rightarrow 3 = e^{0.045t}$$ and now take logarithm and your calculator to get the final answer.