A methanol water mixture is being distilled in a distillation column with a total condenser and a partial reboiler. The pressure is 1.0 atm, and the reflux is returned as a saturated liquid. The feed rate is 250 kmol/h and is a saturated vapor. The feed is 40 mol% methanol. We desire a bottoms product that is 1.1 mol% methanol and a distillate product that is 99.3 mol% methanol. L/D = 4.5. Find the optimum feed stage, the total number of stages, D and B. Assume CMO is valid. Equilibrium data are available in Table 2-7.