Answer:
12.8 years
Step-by-step explanation:
Put the given numbers into the model and solve for t.
[tex]3P_0=P_0e^{.086t}\\\\3=e^{.086t} \qquad\text{divide by $P_0$}\\\\\ln{3}=.086t \qquad\text{take the natural log}\\\\\dfrac{\ln{3}}{.086}=t\approx 12.77[/tex]
It will take about 12.77 years for the population to triple at the current growth rate.