It is stated that the total bill the patient would only pay would be the $25 plus 20% of the original bill. Therefore this would mean that:
25 + 0.2 * X = 200 ---> 1
25 + 0.2 * X = 800 ---> 2
Where X represents the original bill.
Calculating for X in equation 1:
25 + 0.2 * X = 200
0.2 * X = 175
X = 875
Calculating for X in equation 2:
25 + 0.2 * X = 800
0.2 * X = 775
X = 3875
Therefore the original bill ranges from $875 to $3875. The equality equation would be:
$875 ≥ X ≥ $3875