JEE Main 2020 — Solutions Question with Solution

At $300 \mathrm{K}$, the vapour pressure of a solution containing $1$ mole of $\mathrm{n}$ -hexane and $3$ moles of $\mathrm{n}$ -heptane is $550 \mathrm{mm}$ of $\mathrm{Hg}$. At the same temperature, if one more mole of $\mathrm{n}$ -heptane is added to this solution, the vapour pressure of the solution increases by $10 \mathrm{mm}$ of $\mathrm{Hg}$. What is the vapour pressure in $\mathrm{mmHg}$ of $\mathrm{n}$ - heptane in its pure state______?