Among the two fluids that flows into the tank, big amount of A flows with the flowrate of Fa, however the other fluid B which can be catalyst or some component of dye flows in small amount with the flowrate of FB. The volume of tank is V and it is well-mixed. As shown in the Figure 1 some part of B is mixed with the tank exit stream in order to enhance the response of the process. Derive the mathematical model with assumptions and find the transfer functions. Find the response for unit step increase in inlet concentration of material B. 1-P Material A FA Material B FB CB, tank CB, outlet