Microscope Lens Great, Safe Lens Cloth - Recommended Physics Compound Microscope Lens Question?

Physics compound microscope lens question? - microscope lens great, safe lens cloth - recommended

Hello, if someone can me with this problem of physics that would be great, made me very confused at the moment.

Draw a diagram (graph radius scale, can I do if I values) of the provision in the lens of a microscope, so that in total reached an increase of 30, while the focal length of the front lens 4-times the target of 3 -- times increased. You decide (object distance) from the front lens and the focal length of the eyepiece, so that the entire increase can be achieved.

Do I have calculated that 5.3333cm I'm not even sure if this is true.

Thanks in advance!