Problem 4. A two phase mixture containing 40 mole % methanol (M) and 60 mole % water (W) is continuously fed into a distillation column operating at 1atm. The system has a partial condenser and a partial reboiler. The desired separation requires 35 equilibrium stages including the partial condenser and the partial reboiler, and the optimum feed stage is 18 stages below the condenser. That is, if the stage immediately below the condenser is numbered as Stage 1 , then the optimum feed stage is Stage 18. The overall efficiency is E0=0.75 for this case. a. Determine the actual number of stages required using the overall efficiency. b. Determine the actual feed stage using the overall efficiency. For both (a) and (b) be careful to state whether or not the condenser and reboiler are included in the number of stages