A traveling circus with thrill rides charges $9 for admission plus $1.25 for each ride you take. Let r be the number of rides you take. The equation describing the total amount you will pay, T, is T = 1.25r + 9. If you pay $17.75 total, how many rides did you take?
a) 6 rides
b) 7 rides
c) 8 rides
d) 9 rides