You have two lenses at your disposal, one with a focal length 1 = +40.0 cm, the

You have two lenses at your disposal, one with a focal length ƒ1 = +40.0 cm, the other with a focal length ƒ2 = -40.0 cm.

(a) Which of these two lenses would you use to project an image of a lightbulb onto a wall that is far away?

(b) If you want to produce an image of the bulb that is enlarged by a factor of 2.00, how far from the wall should the lens be placed?