A well-insulated, full, water tank containing 197 kg of water initially at 43.9°C is being supplied with 16.7°C water at a rate of 4 kg/min. Water is exiting the tank at the same flow rate so that the mass of water in the tank remains constant. Circulation in the tank keeps the water at a uniform temperature. The specific heat of the water is given as C= 4.2 kJ/kg-K. Determine the time (minutes) at which the water temperature drops to 33°C.