Assuming the validity of the De Priester charts, make the following VLE calculations far the ethane (1)/propane(2)/isobutane(3)/isopentane(4)

Question:

Assuming the validity of the De Priester charts, make the following VLE calculations far the ethane (1)/propane(2)/isobutane(3)/isopentane(4) system:
(a) BVBL P, given x1 = 0.10, x2 = 0.20. x3 = 0.30, and t = 60°C.
(b) DEW P. given y1 = 0.48. y2 = 0 25. y3 = 0.15, and r = 60°C.
(c) BVBL T, x1 = 0.14, x2 = 0-13, x3 = 0.25, and P = 15 bar.
(d) DEW T, given y1 = 0.42, y2 = 0.30, y3 = 0.15, and P = 15 bar.