The distance between the eyepiece and the objective lens in a certain compound microscope is 19.0 cm. The focal length of the eyepiece is 2.45 cm and that of the objective is 0.405 cm. What is the overall magnification of the microscope?
The magnification of a compound microscope is given by:
M = - L/fo (25cm / fe) (where L =distance between lens, fo=focal length of objective, fe=focal length of eyepiece)
For this problem just plug in your numbers and you will get your answer.