Marco decides to take out a $4,000 student loan during his first year in college. If he is charged 10% interest that is compounded annually, how much will the total loan amount equal in four years when he graduates?

Charlie is at an amusement park that has 18 different rides. each ride costs $1.75. the function c(r) = 1.75r represents the total amount of money that charlie will spend if he goes on r rides, but he never goes on the same one more than once. what domain and range are reasonable for the function?