Consider the diagram. the length of segment qs is units

$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

The answer is 90 % because since 20 multiplied by 5 is 100 you would have to do each question multiplied by 5 so 18 times 5 equals ninety percent.