Answer: you sold 10 adult tickets and 11 children tickets.
Step-by-step explanation:
Let x represent the number of adult tickets that you sold.
Let y represent the number of children tickets that you sold.
You sold a total of 21 tickets. This means that
x + y = 21
Admission prices are six dollars for adults and four dollars for children. You sell tickets for admission to your school play and collect a total of $104. This means that
6x + 4y = 104 - - - - - - - - - -1
Substituting x = 21 - y into equation 1, it becomes
6(21 - y) + 4y = 104
126 - 6y + 4y = 104
- 6y + 4y = 104 - 126
- 2y = - 22
y = - 22/ -2 = 11
Substituting y = 11 into x = 21 - y, it becomes
x = 21 - 11 = 10
