In 1950, a city had a population of 20,000. Every year after that, the population increased by 2%. What was the population in 1990?
We can solve this problem using the following equation:
y = final amount
a = initial amount
r = rate of growth
t = time
We can arrange our knowns to solve for the unknown:
The population was 44,200 in 1990.
Below, we have two cities and their associated growth equations:
When will City B’s population overtake City A’s?
We set City B to be greater than City A to determine the exact moment its population becomes greater.
City B's population will overtake City A's after 9.28 years.