1. The problem statement, all variables and given/known data An object 1.25 cm tall is placed 100 cm in front of a convex lens with a focal length of magnitude 50 cm. A concave lens with a focal length of magnitude 20 cm is placed 90 cm beyond the first lens. Where is the final image located? 2. Relevant equations (1/s)+(1/s')=1/f s= object distance from lens s'= image distance from lens f= focal length 3. The attempt at a solution I wasn't sure where to start so I tried find the image distance for the first lens. (1/100cm)+(1/s')=(1/50cm) => (1/100cm)-(1/50cm)=(-1/100cm)=(1/s') => s'= -100 After this i got stuck because I wasn't sure what to do when the image distance is behind the second lens. Thanks in advance.