Rich is driving from philadelphia to speed pittsburgh at 70 miles per hour and michelle is driving from pittsburgh to philadelphia at 65 miles per hour philadelphia and speeds at 300 miles apart how long will it take rich and michelle to meet

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?