Question

In 1990, the population of the U.S. was about 250 million and was growing exponentially

at a rate of about 1% per year. At this rate, in what year will the population have
doubled?

a. 2080
b. 2070
c. 2060
d. 2050

Answer 1

The correct answer is C.

Explanation:

Giving the following information:

Present Value (PV)= 250 million

Future Value (FV)= 500 million

Growth rate (g)= 1% per year

First, we need to calculate the number of years required for the population to double:

n= ln(FV/PV) / ln(1+g)

n= ln(500/250) / ln(1.01)

n= 69.66 = 70 years

It will take 70 years for the population to double.