1. The problem statement, all variables and given/known data Three thin lenses, each with a focal length of 40.0 cm, are aligned on a common axis; adjacent lenses are separated by 52.0 cm. Find the position of the image of a small object on the axis, 80.0 cm to the left of the first lens. 2. Relevant equations 1/s + 1/s' = 1/f 3. The attempt at a solution So I started this question out with doing: 1/80 + 1/s' = 1/40 solving for s' = 80. However, my image ends up being between lens 2 and lens 3, 28 cm from lens 2 and 24 cm from lens 3. Now I'm stuck because I don't know what to do next. Any suggestions would be appreciated, thank you in advance.