Actually, they made the problem too easy!
If you read the problem, you can answer it "in your head".
Given the formula for population N(t) at any time: .
where: is population at
. . . . is the time period elapsed
. . . . is the doubling period of the population.
The population of the United States doubles approx. every 100 years.
In 1980 the population of the U.S was 200 million.
Find the projected population for the year 2180.
In 1980, the population was 200 million.
We are told that the population doubles every 100 years.
By the year 2180 (200 years later), it has doubled twice.
Therefore, the projected population for 2180 is: .