A large well-mixed tank of unknown volume, open to the atmosphere initially, contains pure water. The initial height of the solution in the tank is unknown. At the start of the experiment a potassium chloride solution in water starts flowing into the tank from two separate inlets. The first inlet has a diameter of 1 cm and delivers a solution with a specific gravity of 1.07 and a velocity of 0.2 m/s. The second inlet with a diameter of 2 cm delivers a solution with a velocity of 0.01 m/s and a density of 1053 kg/m3. The single outflow from this tank has a diameter of 3cm. A colleague helps you by taking samples of the tank and outflow in your absence. He samples the tank and determines that the tank contains 19.7 kg of potassium chloride. At the same moment he measures the flow rate at the outlet to be 0.5 L/s, and the concentration of potassium chloride to be 13 g/L. Show that your colleague took the samples after 25 minutes. The tank and all the inlet solutions are maintained at a constant temperature of 80 °C.