A nurse is preparing to administer penicillin G potassium 1,000,000 units intermittent IV bolus. The label on the vial indicates to reconstitute with 50 mL of sterile water to make penicillin G potassium 100,000 units/mL. How many mL should the nurse administer? (Round the answer to the nearest whole number. Use a leading zero if it applies. Do not use a trailing zero.)