Question:

An object is placed 30 cm in front of a lens. A converging lens with focal length of 20cm is placed 20 cm behind the first lens.

An object is placed 30 cm in front of a lens. A converging lens with focal length of 20cm is
placed 20 cm behind the first lens.
An image is formed 15cm to the right of the converging lens.
i) Determine the focal length of the first lens.
ii) What is the magnification of the two lens system?

An object is placed 30 cm in front of a lens. A converging lens with focal length of 20cm is placed 20 cm behind the first lens. An image is formed 15cm to the right of the converging lens. i) Determine the focal length of the first lens. ii) What is the magnification of the two lens system?