The number of adult tickets sold is 142
Explanation:
Step 1:
Let the number of adult tickets sold be x. Then the number of student tickets sold = 3x - 56. Then, cost of adult tickets = 5x and the cost of student tickets = 3.50(3x - 56) = 10.5x - 196. Also, total receipts = $2005
Total cost = Cost of student tickets + Cost of adult tickets
⇒ 2005 = 10.5x - 196 + 5x
⇒ 2201 = 15.5x
⇒ x = 2201/15.5 = 142