A stock bottle of medication contains 500 mg of drug. You used 125 mg for one prescription and 62.5 mg for a second prescription, while the third prescription was for a child and only 25.25 mg were necessary.

a. What quantity (mg) medication has been used? Round to the nearest hundredths.

b. What quantity (mg) of the original medication is left in the stock bottle? Round to the nearest tenths.