Answer:
Step-by-step explanation:
Let x represent the number of $25 tickets sold. Then the total revenue is ...
25x + 15(8100-x) = 164500
10x + 121500 = 164500 . . . . . . collect terms
10x = 43000 . . . . . . . . . . . . . . . subtract 121500
x = 4300 . . . . . . . divide by 10
Then 8100 -x = 3800.
The number of $25 tickets is 4300.
The number of $15 tickets is 3800.