Answer
2 years
Work Step by Step
Insert the given $A,\ P,$ and $r$ into the formula and solve for t.
$12, 000=8000e^{0.203t}\qquad.../\div 8000$
$1.5=e^{0.203t}\qquad .../$apply ln() to both sides..
$\ln 1.5=0.203t\qquad .../\div 0.203$
$ t=\displaystyle \frac{\ln 1.5}{0.203}\approx$1.99736506457$ \approx 2$ years