A convex lens of focal length 15 cm is placed in front of a convex mirror coaxially at a distance of 5 cm from the pole of the mirror. When an object is placed at a distance of 20 cm from the lens, it is found that the image coincided with the object. The radius of curvature of the mirror is:
1
60 cm
2
65 cm
3
50 cm
4
55 cm