Answer:
Step-by-step explanation:
Let x represent the number of adult tickets sold. Then (321-x) is the number of student tickets sold. The total revenue is ...
3.50x + 2.50(321-x) = 937.50
x + 802.50 = 937.50 . . . . . eliminate parentheses, collect terms
x = 135 . . . . . . subtract 802.50; number of adult tickets
321-x = 186 . . . . number of student tickets
135 adult tickets and 186 student tickets were sold.