Suppose a city with population 400,000 has been growing at a rate of 3​% per year. If this rate​ continues, find the population of this city in 25 years.

Answer 1

The general formula for exponential growth and decay is:

P(t) = P₀·(1 + rate)^t

1. P(t) = population at time t
2. P₀ = starting population = 400,000
3. rate = growth or decay rate expressed as a decimal (decay rates are negative) = 3% = 0.03
4. t = years = 25

Plug the numbers into the formula and use your calculator to compute the answer. Round to the nearest whole number since you can't have part of a person.