A bi-convex lens has radius of curvature of both the surfaces same as 1 / 6 cm. If this lens is required to be replaced by another convex lens having…

A bi-convex lens has radius of curvature of both the surfaces same as $\displaystyle 1 / 6 \mathrm{~cm}$. If this lens is required to be replaced by another convex lens having different radii of curvatures on both sides ( $\displaystyle \mathrm{R}_1 \neq \mathrm{R}_2$ ), without any change in lens power then possible combination of $\displaystyle \mathrm{R}_1$ and $\displaystyle \mathrm{R}_2$ is :