250 adult tickets sold
96 child tickets sold
1) We can solve this problem by resorting to a Linear System of Equations.
2) To do that, let's call a adult and c for the children. The first equation relates the costs and the revenue:

And for the second equation, the total number of tickets.

3) So now, let's set this up and solve it by using the Elimination Method

To find c we can plug a=250 into the second equation

4) Thus, the answer is:
250 adult tickets sold
96 child ticket sold