The population of a small rural town in iowa went from 5700 people in 1998 to 7945 in 2005. what is the rate of change in the population for this town?
a) -321 per yr
b) 321 per yr
c) 1135 per yr
d) 1825 per yr

First, the total difference of the amount of people living in the town from 1998 to 2005 is 7945-5700 or 2245 people. To find out how many years it took for this growth, we would need to subtract 1998 from 2005 to get 7 years. So, in 7 years, the town gained 2245 people. If we divide 2245 by 7 to get the unit rate, we will find that the change in population is 320.71... people per year, or if rounded, 321 people per year, which is a.