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?

Domain= [0,18], Range = [0,31.50]
If Charlie will only go to a single ride one time the possible rides he could go on would be 0 rides to all 18 rides for a domain of [0,18]. The output of the maximum and minimum x values would give us 0 dollars for riding 0 rides and 31.50 for riding all 18 (1.75 *0 = 0) and (1.75*18 = 31.50) so the range is [0, 31.50]