Chemistry Question from JEE Main 2026 · 23 January, Shift 2

Two liquids A and B form an ideal solution. At $320 \, \text{K}$, the vapour pressure of the solution, containing $3$ mol of A and $1$ mol of B is $500 \, \text{mm Hg}$. At the same temperature, if $1$ mol of A is further added to this solution, the vapour pressure of the solution increases by $20 \, \text{mm Hg}$. The vapour pressure (in mm Hg) of B in the pure state is _____. (Nearest integer)