Answer:
r = 4
Step-by-step explanation:
First we have to subtract 21.50 from 20.50 because that is how much money it takes to get inside the amusement park.
21.50 - 20.50 = 1
Right now you have only 1 dollar left. now we have to divide 100 by 25 to see how many times you can ride.
100/ 25 = 4
You can ride 4 times