The optical powers of the objective and the eyepiece of a compound microscope are $$100\ \text{D}$$ and $$20\ \text{D}$$ respectively. The microscope magnification being equal to $$50$$ when the final image is formed at $$d = 25\ \text{cm}$$ i.e, the least distance of distinct vision. If the separation between the objective and the eyepiece is increased by $$2\ \text{cm}$$, the magnification of the microscope will be