An intravenous infusion contains 10 ml of a 1: 5000 solution of isoproterenol hydrochloride and 500 ml of a 5% dextrose injection. at what flow rate ? ? (ml/min) should the infusion be administered to provide 0.1 mcg/kg/min of isoproterenol to a 30 lb. patient, and what time interval will be necessary for the administration of the entire infusion?