We wish to distill a mixture of benzene, toluene, and cumene in a distillation column at 101.3 kPa. The column has a total condenser and a partial reboiler. Feed is a saturated liquid that is 25 mole % benzene, 35 mole % toluene, and 40 mole %cumene and is fed at 100 kmol/h. Reflux ratio (L/D) is 2.0. We desire 95 % recovery of toluene in the distillate and 96 % recovery of cumene in the bottoms. The reflux is a saturated liquid, and constant molal overflow is valid. Equilibrium data can be approximated as constant relative volatilities Q8=2.25, an=1.0, Acr= 0.21. a) Use the optimum feed stage and determine the total number of equilibrium contacts required. (Do not use short-cut methods)