Geometrical Optics

An ice cube has a bubble inside. When viewed from one side the apparent distance of the bubble is $$12 \mathrm{~cm}$$. When viewed from the opposite side, the apparent distance of the bubble is observed as $$4 \mathrm{~cm}$$. If the side of the ice cube is $$24 \mathrm{~cm}$$, the refractive index of the ice cube is