Focal length of eye- piece \(f_e=4\,cm\)
Focal length of object is \(f_O=200\,cm\)
Least distance of distinct vision is \(d =25\,cm\)
So, magnifying power of microscope is
\(M=\frac{-f_0}{f_e}\left(1+\frac{f_e}{d}\right)\)
\(M=\frac{-200}{4}\left(1+\frac{4}{25}\right)\)
\(=-58\,cm\)