Chase buys a new Camaro for 55.500. It will lose 15% in value per year He would like to sell the car when it gets to 20,000. When should he sell the car

what is the best model for the situation
f(x)= 55,500*[tex](.15)^{x}[/tex]
f(x)= 55,500*[tex](.85)^{x}[/tex]
f(x)= 55,500*[tex](1.15)^{x}[/tex]
f(x)= 55,500*[tex](1.85)^{x}[/tex]

How many years should he keep it
8 years
7 years
6 years
5 years