Question

An equation for the depreciation of a car is given by y = A(1-r), where y = current value of the car, A = original cost, r = rate

of depreciation, and t = time, in years. The current value of a car is $12,282.50. The car originally cost $20,000 and
depreciates at a rate of 15% per year. How old is the car?

Answer 1

C. 3 years

Explanation:

I can confirm that the answer to your question is C.

Answer 2

Explanation:

y = A(1 - r)^t......y = value of car after t years.....A = original cost....r = rate of depreciation.....t = time in years

y = 12,282.50

A = 20,000

r = 15% = 0.15

12,282.50 = 20,000(1 - 0.15)^t

12,282.50 / 20,000 = 0.85^t

0.614125 = 0.85^t

log 0.614125 = t * (log(0.85))

t = (log 0.614125) / (log 0.85)

t = 3 <=== 3 years old