In the Pb-Sn system, the fraction of total a phase is 3 times the fraction of b phase at eutectic temperature of 182°C, Pb with 19% Sn dissolved in it, Sn with 2.5% Pb dissolved in it, and liquid is in equilibrium. The alloy compositions of tin (Sn) and lead (Pb) are nearly
1
28.6% and 71.4%
2
38.6% and 61.4%
3
48.6% and 51.4%
4
58.6% and 41.4%