Answer:
Step-by-step explanation:
Let "a" represent the number of adult tickets sold. Then the total revenue is ...
5a +3(200-a) = 720
2a +600 = 720 . . . . . . simplify
2a = 120 . . . . . . . . . . . . subtract 600
a = 60 . . . . . . . . number of adult tickets sold
200-a = 140 . . . number of tickets for children sold