Possible binary solutions are, Benzene + Toluene; Benzene + Xylene; Toluene + Xylene and ternary solution is Benzene + Toluene + Xylene. In equimolar solutions, mole fractions are 1∕2 in binary solution and 1∕3rd in ternary solution for each component. ∴ For Benzene + Toluene, P=