Question

During what year will the population of city (a) be at least twice the size of
the population of city (b)? Show all of your work and explain your steps.

Answer 1

Doubling time is the amount of time it takes for a given quantity to double in size or value at a constant growth rate. We can find the doubling time for a population undergoing exponential growth by using the Rule of 70. To do this, we divide 70 by the growth rate (r).