The object distance is equal to image distance in a plane mirror.
For the distance of man from his image to be 5m
The distance of man from mirror + distance of image from the mirror = 5m
Since object distance = image distance
Therefore, 2 distance of man from the mirror = 5m
Distance of man from the mirror = 5/2 = 2.5m
The man is 10m from the mirror at the starting, so he will have to walk 10 – 2.5
= 7.5m towards the mirror for being 5m away from his image.
