Two discs of same mass and different radii are made of different materials such that their thicknesses are 1 cm and 0.5 cm respectively. The…

Two discs of same mass and different radii are made of different materials such that their thicknesses are $\displaystyle 1$ cm and $\displaystyle 0.5$ cm respectively. The densities of materials are in the ratio $\displaystyle 3$ : 5. The moment of inertia of these discs respectively about their diameters will be in the ratio of $\displaystyle \frac{x}{6}$. The value of $\displaystyle x$ is $\displaystyle \_\_\_\_$.