please help with this question. I solved V1, V2. and V3. I need help with V4 which is the PFR. Thank you.

2. A liquid reaction with a rate rA=kCA is taking place at constant temperature and pressure in a series of reactors, the Levenspiel plot for this reaction is shown below. Pure A enters the reactor at FAO=1000 mol/s,CAO=2mol/L.KA=2(1/s). Determine the volume for the reactors in the series