Physics - Rotation Question with Solution | TestHub

The figure shows two solid discs with radius $R$ and $r$ respectively. If mass per unit area is the same for both, what is the ratio of $MI$ of bigger disc around axis $AB$ (Which is $\perp$ to the plane of the disc and passing through its centre) of $MI$ of smaller disc around one of its diameters lying on its plane? Given $M$ is the mass of the larger disc.

($MI$ stands for a moment of inertia)