Astudent answers 80% of the questions on the math exam correctly, if she answers 20 questions correctly. how many questions are on the exam?

There is no question, there is just the answer.

$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