An object has a 20cm distance from a convex mirror with a 10cm radius. Is the image real or virtual? A convex lens with a focal length of 20 cm is placed in front of a convex mirror with a focal length of 7.5 cm. A luminous object is placed in front of the convex lens at a distance of 40 cm from it. What is the distance between the mirror and the lens to get the object's erect image coincident with the object?