I need help with Math!

The physician prescribes a loading dose of procainamide 500 mg in 100 mL NS over 30 min. The label reads procainamide 500 mg per mL. You should add 1 mL of procainamide to 100 mL NS. You should set the infusion pump at 200 mL per hr to deliver this bolus. The loading dose is to be followed with a continuous infusion of procainamide 2 g in 250 mL D5W to run at 2 mg per min. You should set the infusion pump at _____ mL per hr.

I can't figure out why the answer to the last gap is 24 ml per hour. Why is not 15 ml/hr?

Help please!!