Three cstrs are to be used in series in the design of a treatment process. the second reactor has a volume twice that of the first and third reactors. the influent flow has a concentration of 200 mg/l of substance a to be treated, and the flow rate is 400 /min. the reaction is first order, and the rate equation is: the reaction rate constant is 0.40 hr'. determine the following using both the algebraic equation and the graphic solution: a. the mean residence time and volume for each reactor if the conversion of substance a is 90%. b. the concentration of substance a in each reactor and its effluent. c. the total mean residence time and total volume of the three reactors. d. the mean residence time and volume of a single cstr having the same conversion of a to replace the three cstrs.