At 80 C the vapor pressures of pure liquids X, Y, and Z are 385, 190, and 66 mm Hg, respectively.

At 80 °C the vapor pressures of pure liquids X, Y, and Z are 385, 190, and 66 mm Hg, respectively. What pressure must be exerted on the surface of a solution containing one mole of X, three moles of Y, and two moles of Z for boiling point to begin at 80 °C?