A country's population in 1993 was 72 million. In 1996 it was 76 million. Estimate the population in 2003 using exponential growth.

We use the formula for exponential growth:

P = Po exp (kt)

Using the population data from 1993 to 1996, we can solve for the growth rate k

76 = 72 exp (k (3))

76/72 = exp (3k)

ln (76/72) = 3k

k = ln (76/72) / 3 = 0.0180

In 10 years (2003), the population will be:

P = Po exp (0.0180t)

P = 72 exp (0.0180 (10))

P = 86.22 million