Question 424756
Let x = the number of $8 tickets.  
Then 850-x = the number of $12 tickets.
Setting up the problem in equation form, we have
8x + 12(850-x) = 3760 + 4000
Collect terms and solve for x:
-4x + 10200 = 7760 -> x = 610
So they need to sell 610 $8 tickets and 850 - 610 = 240 $12 tickets