How far from a convex lens of focal length 20 cm would you place an object to get a real image enlarged three times ?

How far from a convex lens of focal length 20 cm would you place an object to get a virtual image, which is magnified 3 times ?

An object is placed at a certain distance from a convex lens of focal length 20 cm. Find the distance of the object if the image obtained is. magnified 4 times.

At what distance should be placed from a convex lens of focal length 15 cm to obtain an image three times the size of the object?

A convex lens of focal lengths 30 cm produces 5 times magnified real image of an object What is the object distance ?

An object is placed at a distance 20 cm from a convex lens of focal length 10 cm . Find the image distance and nature of the image .

A convex lens of focal length 20cm is placed 10cm away from a second convex lens of focal length 25 cm. What wil be the location of the image of an object at 30 cm in front of the first lens?