A high school's student council wants to purchase spirit shirts for its upcoming homecoming event. Purchases of 25 shirts or less cost $20 per shirt, plus $20 shipping
and handling. When more than 25 shirts are ordered the price is $15 per shirt, plus S15 shipping and handling. If $720 was spent on shirts, how many shirts did the
student council order?
A. 48
B. 47
C. 37
D. 36