Answer: 13
Step-by-step explanation:
add 24 to 54 and you get 78. divide that by 9 and you get 13.
24 is the total price off
54 is the total he pays
add 54 and 24 to get 78, the original total without any off
9 is the amount each cup costed with the 4 dollars off
divide 78 by 9
13 would be the answer
13- 9 is also 4 dollars
