Answer
8.7 years
Work Step by Step
Insert $A=2(8000)=16,000$,
the given $P$ and $r$ into the formula and solve for t.
$16, 000=8000e^{0.08t}\qquad.../\div 8000$
$2=e^{0.08t}\qquad .../$apply ln() to both sides..
$\ln 2=0.08t\qquad .../\div 0.08$
$ t=\displaystyle \frac{\ln 2}{0.08}\approx$8.664339757$ \approx 8.7$ years.
