A $40wt\%Pb-60wt\%Mg$ alloy is heated to a temperature within the $+L$ phase region as shown in the Animated Figure for the $Pb-Mg$ phase diagram above. If the composition of the $$ phase is $30wt\%Pb,$ determine

$($a$)$ The temperature of the alloy

$Ex$:$123$: $C$

$($b$)$ The coniposition of the liquid phase

Ex: $12$

$wt\%Pb$

$($c$)$ The mass fraction of the $$ phase

$Ex$: $0\mathrm{.}12$

$($d$)$ The mass fraction of the liquid phase

Ex: $0\mathrm{.}12$