Properties of Solids and Liquids: JEE Main 2024 Physics question

A soap bubble is blown to a diameter of $7 \mathrm{~cm}$. $36960 \mathrm{~erg}$ of work is done in blowing it further. If surface tension of soap solution is 40 dyne/$\mathrm{cm}$ then the new radius is ________ cm Take $(\pi=\frac{22}{7})$.