Answer in billions

Question

The population of the world in 1987 was 5 billion and the annual growth rate was estimated at 2 percent per year. Assuming that the world population follows an exponential growth model, find the projected world population in 1993. 

Answer 1

1993 is exactly 6 years after 1987. We also know our principal (initial) amount is 5 billion, with an annual growth rate of 2%. The general equation we need is:

A = P(1 + r)^t

Where A = the amount after growth, P = Principal amount, r = growth rate, and t = time (in years)

Using our formula, we can solve for A:

A = (5000000000)*(1+0.02)⁶

A = 5630812096.32

But since we can't have a non-whole number of people, we'll round our answer to the nearest whole number:

A = 5630812096 people