The radii of curvature of the concave surfaces are \( R \), and the refractive index of the material is \( 1.5 \). Using the lens maker's formula for a spherical surface, the separation between the images of \( O \) formed by each surface is calculated. The distance between the two images is given by: \[\text{Distance between images} = 2R \left( 0.6R + \frac{9}{7} R \right) = 0.114 R\] Consequently, the separation between the images of \( O \) is \( 0.114R \).