In Pb$-$Sn system, the fraction of total $\backslash$alpha phase is $3$ times the fraction of

phase at eutectic temperature of $183$C$,$ Pb with $19\%$Sn dissolved in it$,$

Sn with $2\mathrm{.}5\%$ Pb dissolved in it and liquid is in equilibrium. The alloy

composition of Sn and Pb are nearly?Composition $($at$\%$ Sn$)$