How does 3v3 ranked placement work?

My friend and I just finished our final game of placements in 3v3 going 5/5 and we ended up getting Bronze V. So I'm wondering how going 5/5 gets the same result as 0/10. I know order of wins/loses and stuff matters so we went 2W-3L-2W-1L-1W-1L. With these results we weren't expecting to be silver but at least mid bronze. It's no big deal as I don't really care much about ranked I was just curious.