3) A plant has two streams containing benzene and toluene, one with 37% benzene and one with 68% benzene. About equal amounts of the two streams are available, and a distillation tower with two feed points is proposed to produce 98% benzene and 99% toluene in the most efficient manner. However, combining the two streams and feeding at one point would be a simpler operation. For the same reflux rate, calculate the number of ideal stages required for the two cases. Comment on the design of the column for each case