Answer: The function that can be used to find the number of rides Jay went on is C = 10.50 + 4.50r, where C is the total cost and r is the number of rides. In this case, we know that Jay spent a total of $46.50 on entrance fees and rides, so we can plug this value into the equation and solve for r:
46.50 = 10.50 + 4.50r
Subtracting 10.50 from both sides, we get:
36 = 4.50r
Dividing both sides by 4.50, we find that Jay went on r = 8 rides.