The dinsities of two solid spheres $A$ and $B$ of the same radii $R$ vary with radial distance $r$ as $\rho_A(r)=k\left(\frac{r}{R}\right)$ and $\rho_B(r)=k\left(\frac{r}{R}\right)^5$, respectively, where $k$ is a contant. The moments of inertia of the individual spheres about axes passing through their centres are $\mathrm{I}_{\mathrm{A}}$ and $\mathrm{I}_{\mathrm{B}^{\prime}}$, respectively, If $\frac{\mathrm{I}_{\mathrm{B}}}{\mathrm{I}_{\mathrm{A}}}=\frac{\mathrm{n}}{10}$, the value of n is: