A brine solution of salt flows at a constant rate of 9 L/min into a large tank that initially held 100 L of brine solution in which was dissolved 0.4 kg of salt. The solution inside the tank is kept well stirred and flows out of the tank at the same rate. If the concentration of salt in the brine entering the tank is 0.04 kg/L, determine the mass of salt in the tank after t min. When will the concentration of salt in the tank reach 0.02 kg/L? If x equals the mass of salt in the tank after t minutes, first express = input rate - output rate in terms of the given data. dt =0 Determine the mass of salt in the tank after t min. mass = kg When will the concentration of salt in the tank reach 0.02 kg/L? The concentration of salt in the tank will reach 0.02 kg/L after minutes. (Round to two decimal places as needed.)