Advanced Functions
posted by Sara on .
he value of a new car depreciates at a rate of 12% per year.
Write an equation to represent the approximate value of a car purchased for $23 000.
Determine the value of the car two years after it is purchased.
Approximately how many years will it take until the car is worth $2300?

1. V= C  rtC,
Eq: V = C(1  rt).
V = value.
C = cost.
r = rate expresed as a decimal.
t = time in years.
2. V = 23000(1  0.12*2),
V = 23000 * 0.76 = 17480.
3. V = 23000(1  0.12t) = 2300,
23000(1  0.12t) = 2300,
Divide both sides by 23000:
1  0.12t = 0.1,
0.12t = 0.1  1 = 0.90,
t = 0.90 / 0.12 = 7.5 yrs. 
Correction:
1. Eq: V = C(1r)^t
2. V = 23,000(10.12)^2 = $17,811.20
3. V = 23,000(10.12)^t = 2300
(0.88)^t = 0.1
t*Log(0.88) = Log0.1
t = Log 0.1/Log0.88 = 18 Years.