Multi Component Distillation

PLEASE ANSWER THIS WITH STEP-by-STep solution. Thank you~

A liquid feed to a distillation tower at 405.3 kPa abs is fed to a distillation tower. The composition in mole fractions is as follows: n butane (XA = 0.40), n - pentane (XB = 0.25), n-hexane (xc = 0.20), n-heptane (xp = 0.15). Calculate: (a) the boiling point and the vapor in equilibrium with the liquid; (b) the dew point of the feed and the composition of the liquid in equilibrium; and (c) the temperature and composition of bothe phases when 40% of the feed is vaporized in a flash distillation