A standard "35-mm" slide measures 24.0 mm by 36.0 mm. Suppose a slide projector produces a 60.0-cm by 90.0-cm image of the slide on a screen. The focal length of the lens is 12.0 cm.
(a) What is the distance between the slide and the screen?
(b) If the screen is moved farther from the projector, should the lens be moved closer to the slide or farther away?