Properties of Solids and Liquids: JEE Main 2025 Physics question

A vessel with square cross-section and height of 6 m is vertically partitioned. A small window of 100 cm$^2$ with hinged door is fitted at a depth of 3 m in the partition wall. One part of the vessel is filled completely with water and the other side is filled with the liquid having density $1.5 \times 10^3$ kg/m$^3$. What force one needs to apply on the hinged door so that it does not get opened ? (Acceleration due to gravity $= 10$ m/s$^2$)