Question $2.($Phase Diagram$)$

According to the $\backslash (\backslash$mathrm$\{$Pb$\}-\backslash$mathrm$\{$Sn$\}\backslash )$ binary phase diagram shown below,

a$)$ Find Point A $,$ for a $\backslash (\backslash$mathrm$\{$Pb$\}-30\backslash$mathrm$\{$wt$\}\backslash \%\backslash$mathrm$\{$Sn$\}\backslash )$ alloy at $225$ C

b$)$ Construct a tie$-$line on the figure and read off the two phases and calculate their $\backslash \%$compositions. $($Hint: Use lever rule$)$

c$)$ The same alloy at Point A is slowly cooled to $200$ C $.$ At this temperature, identify the phases and calculate their $\backslash \%$compositions.$($Hint: Use lever rule$)$