A converging lens held near a flashlight is used to put an image of the bulb
on a wall that is 1.60m from the lens. With the flashlight fixed, the lens
is moved closer to the wall and a sharp image is again formed when the lens
is 15cm from the wall.
a. What is the focal length of the lens?
b. How far is the flashlight bulb from the wall?
I cannot figure it out and am getting very frustrated. Any help would be