A Sanddune stands 5 feet above sea level the hill is eroding at a rate of 1 foot/ 20 years light wire represent the height of the Sandune after X years which represents the situation

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?