Answer: 51 child tickets were sold that day.
Step-by-step explanation:
Let x represent the number of child admission tickets that were sold on Monday.
Let y represent the number of child adult tickets that were sold on Monday.
On Monday, 132 tickets were sold. It means that
x + y = 132
At the movie theatre, child admission is $5.20 and adult admission is $9.00. On Monday, the total sales was $994.20. This means that
5.2x + 9y = 994.2- - - - - - - - - - - -1
Substituting x = 132 - y into equation 1, it becomes
5.2(132 - y) + 9y = 994.2
686.4 - 5.2y + 9y = 994.2
- 5.2y + 9y = 994.2 - 686.4
3.8y = 307.8
y = 307.8/3.8
y = 81
x = 132 - y = 132 - 81
x = 51