An azeotrope consists of \(40.0 \mathrm{~mol}\) per cent acetone (1) and \(60.0 \mathrm{~mol}\) per cent methanol at \(760 \mathrm{~mm} \mathrm{Hg}\) and \(310 \mathrm{~K}\). At \(310 \mathrm{~K}\), the vapour pressure of acetone and methanol are \(780 \mathrm{~mm} \mathrm{Hg}\) and \(542 \mathrm{~mm} \mathrm{Hg}\) respectively. Calculate the van Laar constants.