Overall mass balance for dilution process. a well-stirred storage vessel contains 10 000 kg of solution of a dilute methanol solution (wa = 0.05 mass fraction alcohol). a constant flow of 500 kg/min of pure water is suddenly introduced into the tank and a constant rate of withdrawal of 500 kg/min of solution is started. these two flows are continued and remain constant. assuming that the densities of the solutions are the same and that the total contents of the tank remain constant at 1 kg of solution, calculate the time for the alcohol content to drop to 1.0 wt%.