Respuesta :
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.
Let U = upper
Let L = lower
U + L = 2615
99U + 77L = 247071 You can make your life slightly easier by dividing this equation through by 11
9U + 7L =24461 Multiply the first equation by 7
7U + 7L = 2615 * 7
7U +7L = 18305
====================
Combine the 2 new equations
9U + 7L = 24461
7U + 7L = 18305 Subtract
2U = 6156 Divide by 2
U = 6156 / 2
U = 3078
The Number of Upper Level Tickets sold was 3078