Gravitation

Two neutral bodies of masses $m_1$ and $m_2$ are kept at a distance of $r \mathrm{~cm}$ from one another in a vacuum medium. A gravitational force Fracts between the two bodies. The entire set-up is then transferred, as it is, to a water medium. The force between the bodies is then $\mathrm{F}_{\mathrm{w}}$. The ratio of $F_v$ to $F_w$ is: