How far from the eyepiece is the image formed by the objective?

[sona1177]

Homework Statement

A microscope has an eyepiece of focal length 2.50 cm and an objective of focal length 4.60 cm. The eyepiece produces a virtual image at the viewer's near point (25.0 cm from the eye).

a) How far from the eyepiece is the image formed by the objective? ANswer: 2.27 cm -This is correct :)
b) If the lenses are 21.0 cm apart, what is the distance from the objective lens to the object being viewed ANswer: 6.10 cm. This is correct :)
c) What is the angular magnification? Answer: -33.3 This is WRONG :(

Here is what I did:
L=(Distance between lens) - (objective focal length) - (eye piece focal length)

so,

L= 21.0-4.60 - 2.50
L=13.9

I know that M=-LN/(objective focal length * object distance from eye piece)
So plugging in L=13.9
N=25
Fo=4.60
pe=2.27 i get -33.3 and not -33.8

Homework Equations

The Attempt at a Solution

 

[darkys]

I have stated my attempt at a solution above. I know that -33.3 is wrong, so I must have made a mistake in my calculation but I'm not sure where.