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 points and the heats of melting of solid A and Bares $7.$ AN A $400$K $3000$ cal$/$mol B $390$K $2800$ cal$/$mol