Wallpaper costs $16 per roll, and border costs $9 per roll. If 12 rolls of wallpaper and 6 rolls of border are needed for one room, find the total cost of the
wallpaper and border.

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?