Answer:the cost of a children's ticket is $3
Step-by-step explanation:
Let x represent the cost of an adult ticket.
Let y represent the cost of a child ticket.
200 adult tickets and 100 children tickets are sold. The revenue is 2100. This means that
200x + 300y = 2100 - - - - - - - - - 1
An adult movie ticket cost $3 more than a child's ticket. This means that
x = y + 3
Substituting x = y + 3 into equation 1, it becomes
200(y + 3) + 300y = 2100
200y + 600 + 300y = 2100
200y + 300y = 2100 - 600
500y = 1500
y = 1500/5 = 3
x = y + 3 = 3 + 3 = $6
