Jimmy is selling used books at a yard sale. A customer buys 9 books at a cost of $0.75 each and pays with a $20.00 bill. Jimmy must determine c, the amount of change in dollars he should give the customer. Which equation represents c?
20 minus 0.75 c = 9
20 minus 0.75 = 9 c
0.75 (9) + c = 20
0.75 c + 9 = 20