Answer:
Step-by-step explanation:1) Charges are:
Flat fee: 500
First 100 tickets: 20(100) = 2000
Tickets over 100: 17 ( x - 100), where x is the number of tickets.
2) Total charges: 500 + 2000 + 17(x - 100) = 2500 + 17(x - 100)
3) Average cost per ticket = total charges / number of tickets
⇒ [2500 + 17(x - 100) ] / x
4) limit as the number of tickets, x, becomes very high ⇒ x → ∞
⇒

5) Here is the demostration of the value of that limit:
2500 / x + 17x / x - 1700/x = 0 + 17 + 0 = 17