I had thrown the question before, but the solution was not clear at all. I would appreciate it if you could solve the question by writing, please.

3- For the following liquid phase parallel reaction system, AR(desired)AS:rR=k1CA:rS=k2CA:k1=2s1k2=1.5s1 a-) Obtain the instantaneous yield (R/A) expression. b-) Calculate the concentration of R at the reactor exit if the reaction is carried out in PFR and in CSTR when CA0=1mol/L,g0=10L/s, and overall conversion of A is 0.9. c-) Calculate the volume of PFR and CSTR reactors if the overall conversion of A is 0.9(CA0=1 mol/L) Note: Pure A is fed to the reactors