Question

Gary bought a car for $40,000. If V = 40,000(.85)t represents the value of the car after t years, how long will it take the car to be worth less than one-fourth of its purchase price?

Answer 1

40000*1/4=10000
10000=40000(0.85)^t solve for t
t=log(10,000÷40,000)÷log(0.85)
t=8.5 years
Less than one-fourth
Assume 9000
T=log(9,000÷40,000)÷log(0.85)
T=9 years