QUESTION 1 A tank holds 60L of water-salt solution in which 4kg of salt is dissolved. Water flow into the tank at the rate of 3L/min and salt solution overfiows at the same rate. If the mixing in the tank is adequate to keep the concentration of salt in the tank uniform at all time, how much salt is in the tank at the end of 60 min. Assume that the density of the sait solution is essentially the same as that of water