Two mixing tanks A and B with capacities of 200 gallons each are connected in series. Tank A initially contains 150 gal of salt solution with a concentration of 0.5 lb/gal while tank B contains 100 gal of pure water. Pure water enters tank A at a rate of 4 gal/min. The outlet stream from tank A then flows into tank B at a rate of 4 gal/min. If the solution coming out of tank B flows at 2 gal/min, determine the following:

a. Draw a schematic diagram of the system.

b. Mass of salt coming out of tank B at any time and the concentration of the salt solution after 10 minutes of operation.

c. Concentration of the solution coming out of tank B just before overflow.