Amedical plan requires a patient to pay a $25.00 copay plus 20% of all charges incurred for a medical procedure. if the average bill for a patient is between $200 and $800, find the range of the original bill

Patient's payment = $25.00 + 20% * charges

Final payment = $200 => $ 200 = $25  +  0.2 * charges

=> charges = [$200- $ 25 ] / 0.2 = $875.

Final payment = $800 => $800 = $25 + 0.2 * charges

=> harges = [$800 - $25] / 0.2 = $3875

=> The range of the original bill is [$875, $3875]