How Do You Calculate the Focal Lengths of Microscope Lenses?

[strawberry7]

Homework Statement

A microscope is made in a tube 25.0 cm long. It magnifies 5.00 x 10to the 2 times, 50.0 times by the objective lens and 10.0 times by the eyepiece. What are the focal lengths of the two lenses?

Homework Equations

m= H/h=-q/p
q= p(f) / p-f
H= -h(q/p)

The Attempt at a Solution

GIVEN m= 5.00 * 10 to the 2
REQUIRED f= focal length = ? cm is what i am trying to find
I don't think i have the right equation but i don't know which equation to use.

 

[krateesh]

u have got f-ob + f-eye = 25 cm...
Now...f-ob / f--eye = m

now u have two variables and two equations ...just solve it out...i couldn't get the later part of the question actually...