find the coordinates of the intersection of the diagonals of parallelogram PQRS with vertical P(-5,5) Q(2,5) , R(4,-3) and S(-3,-3)

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?