42) 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?

Let's construct an equation for Canton's population increase as 7220+80n and Holly Spring's population increase with 3200+120n, where n is the number of years. We have to set these equations to each other in order to find when the population of these two places are equal. 3200+120n=7220+80n and n=100.5. After 100 and half years