$3-$ Consider an Al$-60\backslash \%$ Si alloy $($see Figure $2).$

i$-$ Name and write the invariant reaction present in this system. ii$-$ Determine;

$($a$)$ if the alloy is hypoeutectic or hypereutectic;

$($b$)$ the composition of the first solid to form during solidification;

$($c$)$ the amounts and compositions of each phase at $\backslash (578^\{\backslash$circ$\}\backslash$mathrm$\{$C$\}\backslash )$;

$($d$)$ the amounts and compositions of each phase at $\backslash (576^\{\backslash$circ$\}\backslash$mathrm$\{$C$\}\backslash )$;

$($e$)$ the amounts and compositions of each phase at $\backslash (25^\{\backslash$circ$\}\backslash$mathrm$\{$C$\}\backslash ).$