The slab of a material of refractive index \(2\) shown in figure has curved surface \(APB\) of radius of curvature \(10\ cm\) and a plane surface \(CD\). On the left of \(APB\) is air and on the right of \(CD\) is water with refractive indices as given in figure. An object \(O\) is placed at a distance of \(15\ cm\) from pole \(P\) as shown. The distance of the final image of \(O\) from \(P\) as viewed from the left is