Suppose that at 370 K pure solid A is in equilibrium with a liquid solution containing 60 mol% A and 40 mol % B. Use this information and the Margules equation, estimate the composition of the A and B liquid mixture when it is in equilibrium with pure solid B at the same temperature. The melting temperature and the heat of fusion for solid A and B are: A: 400K and 3000 cal/mol , B: 390K and 2800 cal/mol.