Answer:
- 1650 tickets at $9
- 810 tickets at $7
Explanation:
It usually works well to let the variable represent the quantity of the highest contributor to the mix. Here, we can let x be the number of $9 tickets. Then the total revenue is ...
$7(2460 -x) +$9(x) = $20520
2x = 3300 . . . . . . . . . . . . . . . . . . . subtract 17220 and collect terms
x = 1650 . . . . divide by 2 . . . (number of $9 tickets)
2460-x = 810 . . . (number of $7 tickets)
1650 tickets were sold at $9, and 810 tickets were sold at $7.