In a film projector, the film acts as the object whose image is projected on a screen

Question:

In a film projector, the film acts as the object whose image is projected on a screen (Fig. 23-59). If a 105-mmfocal- length lens is to project an image on a screen 25.5 m away, how far from the lens should the film be? If the film is 24 mm wide, how wide will the picture be on the screen?