Answer:
17.6 years
Step-by-step explanation:
There are currently 73 million cars in a certain country, decreasing by 1.7% annually.
How many years will it take for this country to have 54 million cars? Round to the
nearest year.
We use the formula
y = a(1 - r)^t
a = Initial amount = 73 million cars
y = Future amount = 54 million cars
r = decreasing rate = 1.7 % = 0.017
t = time is unknown
54,000,000 = 73,000,000(1 - 0.017)^t
Divide both sides by 73,000,000
54,000,000/73,000,000 = (0.983)^t
0.7397260274 = (0.983)^t
Take the logarithm of both sides
log 0.7397260274 = Log (0.983)^t
log 0.7397260274 =t log (0.983)
t = log 0.7397260274/log 0.983
t = -0.13092910029/-0.00744648216
t = 17.5826783005 years
Approximately = t = 17.6 years
