A distillation column treats a mixture containing 60 mol% of component A and 40 mol% of component B at total pressure of 1 kPa. The mixture was separated through distillation process to give a distillate containing 90 mol% of component A and bottom containing 85 mol% of component B. The feed is liquid at its boiling point. Given relative volatility AB=2.5 and molecular weight for A and B are 78 kg/kmol and 92 kg/kmol respectively. Based on Table 1,

a) determine YA1, YA2 and YA3.(6 marks) b) determine the minimum reflux ratio, Rmin. (6 marks) c) By using McCabe-Thiele Method, determine the number of stages if the reflux ratio, R is 4.32 times of minimum reflux ratio, Rmin. (8 marks)