The following non$-$elementary liquid phase reaction $3AkB+C$ that has a rate of

caction $r_B=\frac{15C_A}{(1+C_A^2)}(\frac{\text{m}\text{o}\text{l}}{m^{\text{'}}s})$ is conducted in two CSTRs connected in parallel. The fresh pure $A$

nolar and volumetric flow rates are $100mo\frac{l}{m}in$ and $25\frac{m}{m}in.55\%$ of the feed goes to the first

$20m^{3}CSTR.$ The final $($mixed$)$ conversion of $A$ is $75\%.$

$1-$ Calculate the volume of the second CSTR$.$