Let x represent lower level tickets that cost $77
Let y represent upper level tickets that cost $99
Cost equation: 77x + 99y = 247,071
Tickets equation: x + y = 2615
Using the elimination method, multiply the second equation by -77:
77x + 99y = 247,071
-77x - 77y = -201,355
--> 22y = 45,716
--> y = 2,078
Now plug "y" into either equation and solve for "x". I chose the Tickets equation. x + y = 2615 → x = 2615 - y → x = 2615 - 2078 → x = 537
Answer: lower level = 537 tickets, upper level = 2078 tickets.