A brine solution of salt flows at a constant rate of 4L/min into a large tank that initially held 100L of pure water. The solution inside the tank is kept well-stirred and flows out of the tank at a rate of 3L/min. If the concentration of salt in the brine entering the tank is 0.2Kg/L, determine the mass of the salt in the tank after t minutes. When will the concentration of salt in the tank reach 01.kg/L?