Suppose a brine solution containing 0 . 2 kg of salt per liter runs into a tank initially filled with 500 L of water containing 5 kg of salt. The brine enters the tank at a rate of 5 L/min. The mixture, kept uniform by stirring, is flowing out at a rate of 5 L/min. (a) Find the concentration in kilograms per liter, of salt in the tank after 10 minutes. (b) After 10 minutes, a leak develops in the tank and an additional liter per minute of mixture flows out of the tank. What will be the concentration, in kilograms per liter, of salt in the tank be 20 min after the leak developed.