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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.

  161 million

Step-by-step 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.