I need the whole solution with steps please

For the mixture n-hexane, n-heptane and n-octane at p=150kpa the vapor molar composition are 0.5,0.2,0.3, Assuming ideal gas law at 500k. what will be molar-value of the mixture (R=8.314j/mol.k) a) 27.7m3/mol b) 2.77m3/mol c) 0.277m3/mol d) 0.0277m3/mol