A vessel of volume V = 6.0 1 contains water together with its saturated vapour under a

Question:

A vessel of volume V = 6.0 1 contains water together with its saturated vapour under a pressure of 40 arm and at a temperature of 250 °C. The specific volume of the vapour is equal to Vv = 50 1/kg under these conditions. The total mass of the system water-vapour equals m = 5.0 kg. Find the mass and the volume of the vapour.