Final answer:
To solve this problem, we can use a system of equations to represent the number of adult and children's tickets sold. By solving the system of equations, we find that 11 children's tickets were sold.
Step-by-step explanation:
To solve this problem, we can use a system of equations. Let x represent the number of adult tickets sold, and let y represent the number of children's tickets sold. We have the following equations:
- x + y = 21 (total number of tickets sold)
- 6x + 4y = 104 (total amount collected)
We can solve the system of equations using substitution or elimination. Let's solve it using elimination:
- Multiply the first equation by 4: 4x + 4y = 84
- Subtract the second equation from the first: (4x + 4y) - (6x + 4y) = 84 - 104
- -2x = -20
- Divide both sides by -2: x = 10
Substitute the value of x into the first equation to find the value of y:
- 10 + y = 21
- y = 21 - 10
- y = 11
Therefore, 11 children's tickets were sold.