60 children tickets and 190 adult tickets were sold.
Explanation:
Let the no. of adult tickets sold be 'a'
Let the no. of children tickets sold be 'c'
Total tickets sold = 250
Cost of 1 children ticket = $2.5
Cost of 1 adult ticket = $4
Total money collected= $910
Given that,
a + c = 250
a = 250 - c
4a + 2.5c = 910
Substitute a value
4(250 - c) + 2.5c = 910
1000 - 4c + 2.5c = 910
1000 - 1.5c = 910
-1. 5c = -90
1.5c = 90
c = 90/1.5
c = 60
a + c = 250
a + 60 = 250
a = 190
60 children tickets and 190 adult tickets were sold.