Question

An equation for the depreciation of a car is given by y = A(1 – r)t , where y = current value of the car, A = original cost, r = rate of depreciation, and t = time, in years. The value of a car is half what it originally cost. The rate of depreciation is 10%. Approximately how old is the car?

Answer 1

6.6 y/o

Explanation:

correct on edg

Answer 2

y - current value of the car;
A - original cost;
t -time in years;
r - rate of depreciation;
r = 10% = 0.1
y = A ( 1 - r ) ^t
1/2 A = A ( 1 - 0.1 ) ^t / : A
0.5 = 0.9 ^ t

`t = log_(0.9)0.5`
t = 6.5
Answer: The car is approximately 6.5 years old.