Answer :
We will first calculate the value of b using the given infomation:
[tex]V(5)=V_0\cdot e^{5\cdot b}[/tex][tex]900=5000\cdot e^{5\cdot b}[/tex][tex]\frac{900}{5000}=e^{5\cdot b}[/tex][tex]\frac{9}{50}=e^{5\cdot b}[/tex][tex]b=\frac{1}{5}\log (\frac{9}{50})[/tex]That must be the rate of depreciation. Now lets find the value of the car 8 years after:
[tex]V(8)=5000\cdot e^{\frac{8}{5}\cdot\log (\frac{50}{9})}[/tex][tex]V(8)\approx321.67[/tex]