Which equation represents the inverse function n(a), which takes the money
raised as input and returns the number of tickets sold as output?

Google it that might work

$250 deductible means jane must pay the first $250 of her bill. so the insurance company paid = (80% of bill) - deductible = (0.8 x $2550) - $250 = $2040 - $250 = $1790 and jane's cost is = (bill) - (insurance payment) = $2550 - $1790 = $760