Answer:
The answer is 9.
Step-by-step explanation: Things to know: c is total cost and t tickets. 800 is the total cost so plug it in to c. You want to get t (tickets) alone.
original: c(t)=87.50t+12.50
Now with the 800: 800=87.50t+12.50
Subtract 12.50 to both sides: 787.5=87.50t
Divide 87.50 to both sides: 9=t
Hopefully this helped. :]