According to the 2000 census the population of canton was 7,720. holly spring's population was 3,200. canton's population increases at a rate of 80 people a year and holly spring's population increases by 120 people a year. which equation may be used to determine the number of years before the populations are equal?

Firstly, the rate of increase of Canton = 80/7720 = 0.010
The rate of increase of HP = 120/3200 = 0.0375
Apply  the formula of compound interest==> A =A'(1+i)^n
The population will be equal when the following equality is satisfied

7720(1+0.01)^n = 3200(1+0.0375)^n

or

7720x1.01^n = 3200x1.0375^n

Divide both sides by 3200 ===>(193/80)x1.01^n=1.0375^n