we and image approach each other at speed of 2m/s.
Let distance between you and mirror = x meters.
so image formed behind the mirror at distance of x meters.
Now distance between you and your image = 2x meters.
let you have taken time to reach mirror = t sec.
so speed =x/t m/sec.
But image covered distance =2x in tsec.
so speed=2x/t m/sec.