An object, 4.0 cm in size, is placed at 25.0 cm in front of a concavemirror of focal length 15.0 cm.

An object, 4.0 cm in size, is placed at 25.0 cm in front of a concave
mirror of focal length 15.0 cm. At what distance from the mirror
should a screen be placed in order to obtain a sharp image? Find
the nature and the size of the image.