On a number line, two convex lenses are placed. At origin is the lens 1 with focal length of 30 cm and on 100 cm on number line is the lens 2 with focal length of 40 cm. An object is placed at the point of 40 cm. Find the positions of any three images.

There would be 3 images formed.... First the image of object on lens 1.... .. the image of object on lens 2............. Third the image of lens 1 on lens 2....... By applying lens formula the image of object on lens 1 is situated at a distance of 120 cm in negative as the object is at right of the lens 1.............. By applying lens formula the image of object on lens 2 is located at a distance of 120 cm from lens 2 that is at the point of 220(100+120) cm on number line........... By again applying lens formula the image of lens 1 on lens 2 is obtained at a distance of 200/3 cm from lens 2 that is 500/3(100+200/3)cm on the no. line....