Answer
$7.0$ years
Work Step by Step
Solve the given formula for $ t.$
$ A=Pe^{rt}\quad $ ... $/\div P $
$(A/P)=e^{rt}\quad $ ... $/\ln(...)$
$\ln(A/P)=rt\quad $ ... $/\div r $
$ t=\displaystyle \frac{\ln(A/P)}{r}$
Insert the values given in the table.
$ t=\displaystyle \frac{\ln(3)}{0.157}\approx $6.9975 (round to 1 dec. place)
