Consider an $25$ wt $\%$ Si$,75$ wt$\%$ Al alloy :

a$)$ What will be composition of the first solid to form during solidification?

b$)$ What will be phases at $578C($i$.$e$.$ just above the eutectic temperature of $577C)?$ What will be their compositions?

c$)$ The weight fractions of each phase at $578C?$