In a binary phase diagram for components $A$ and $B$, the alloy composition C₀​ (40% $A$, 60% $B$) is cooled at a constant temperature $T$, where it enters a two-phase region containing liquid (L) and solid (α) phases. At this temperature, the compositions of the liquid and solid phases are 70% $B$ and 50% $B$, respectively. Using the lever rule, calculate the fraction of the solid (α) phase in the alloy at temperature $T$.