Consider the mixing process shown in the figure. A mixing chamber initially contains 2 liters of a clear liquid. Clear liquid flows into the chamber at a rate of 10 liters per minute. A dye solution having a concentration of 0.5 kilograms per liter is injected into the mixing chamber at a constant rate of liters per minute. When the mixing process is started, the well-stirred mixture is pumped from the chamber at a rate of liters per minute.

(a) Develop a mathematical model for the mixing process. Let represent the amount of dye in kilograms in the mixture.
kg / min

(b) The objective is to obtain a dye concentration in the outflow mixture of 0.2 kilograms per liter. What injection rate is required to achieve this equilibrium solution?
L / min

Would this equilibrium value of be different if the fluid in the chamber at time contained some dye?

(c) Assume the mixing chamber contains 2 liters of clear liquid at time . How many minutes will it take for the outflow concentration to rise to within 4% of the desired concentration of 0.2 kilograms per liter?
min
 

You can earn partial credit on this problem.