Two convex lense are given in the figure A and figure B.which lens has less focal length

Two convex lense are given in the figure A and figure B.Which has more power

Two convex lense are given in the figure A and figure B.Can these lenses act as diverging lenses in any condition?

When an object is placed at a distance of 15 cm from a convex lens, a real image is formed at a distance of 30 cm. What is the focal length of the lens?

What is the focal length of a convex lens of focal length 30 cm in contact with a concave lens of focal length 20 cm? Is the system a converging or a diverging lens? Ignore thickness of the lenses.