But one thing if I reply to any other person post with a valid answer then will it help to improve my rank???
You will rank up to Jr. Member with about 2 weeks using the forum (activity)
To get to higher ranks you will need Merit.
To get merit you need to post something that someone finds useful. If your posts helps someone, then he can award you with a merit.
With 10 merits you will reach Member status.
So the fastest way to rank up is to make good quality posts. For your information, this topic is a shit quality post (as it's duplicated by your old post), and you will not get any merits from it.