Yet another question.

Answer:
t= 3 years
Step-by-step explanation:
So far we have 2 useful relationships[tex]P_{t}= P_{o} e^{r*t}[/tex] and [tex]P_{t}=2P_{0}[/tex]
Now, clearing t
[tex]P_{t}= P_{o} e^{r*t} \\\frac{ P_{t}}{P_{o}} = e^{r*t}\\\frac{2 P_{0}}{P_{o}} = e^{r*t}\\2 = e^{r*t}[/tex]
I apply logarithm
[tex]log(2)=r*t\\ t=\frac{log(2)}{r}\\t=\frac{0.3}{0.1} \\ t=3[/tex] years
Done