Question

6 of

A country's population in 1990 was 154 million.
In 2001 it was 159 million. Estimate
the population in 2005 using the exponential
growth formula. Round your answer to the
nearest million.

Answer 1

161 million

Explanation:

The growth factor over the period from 1990 to 2001 (11 years) is ...

growth factor = (159/154)

Then an exponential equation for the population growth could be ...

p(t) = 154(159/154)^(t/11)

where t is the number of years since 1990.

__

In 2005, the value of t is 15, so the model predicts a population of ...

p(15) = 154(159/154)^(15/11) ≈ 160.86 . . . . million

The population is estimated to be 161 million in 2005.