Ed is undergoing surgery for an old football injury and must be anesthetized. The anesthesiologist knows Ed will be "under" when the concentration of sodium pentathol in his blood is at least 50 milligrams per kilogram of body weight. Suppose that Ed weighs 1 00 kg (220 pounds) and that sodium pentathol is eliminated from the bloodstream al a ra1e proportional to the amount present. If the half-life of 1he drug is 10 hours, what single dose should be given to keep Ed anesthetized for three hours?