Its based on elo not rank
whenever you win a game your elo which starts at 1600 i think goes up by .1 or 1 per win, every time you lose a game its like 2 or .2, basically if you lose a game you lost more then you gained.
and to improve your rank it depends on the elo of those with near ranks near you.
your rank isnt any better cuz people with similar ranks have a higher elo than you, if by chance you get an elo of 1800 and the #1 rank has an elo of 1700 or anything less than 1800 you get that rank.