seperation processes help

We are separating a binary mixture of 40 mole % benzene (component "A") and 60 mole % ethylene dichloride (component "B") in a distillation column with a partial reboiler and a total condenser. Benzene is the most volatile component. The feed rate is 750 moles/ht and the feed is a saturated vapor. The desired distillate product composition is 99 2 mole benzene and the desired bottoms product composition is 0.5 mole % benzene. The reflux is a saturated liquid and constant molal overflow can be assumed The equilibrium data can be approximated with an average relative volatility an111 a Use the Fenske equation to show that the number of stages required at total reflux, N... = 96.9 including the partial reboiler b. Using the Underwood equations (Eq (7-29) & Eq (7-25)], show that the minimum external reflux ratio R. 23.9. Estimate the total number of stages required for this separation, using the Gilliland correlation for R=LD 1.4*(L/D) C