Aboat takes 1 hr longer to go 36 km up a river than to go down the river. if the boat travels 15 km/h in still water, what is the speed
of the current?

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?