[jay_shark]

You need to focus on a reference point . The formula tells you the probability of dropping 20 buy-ins if you start off with 20 buy-ins . So this means that if you win 10 in a row and drop 20 in a row , then you're down only 10 buy-ins from 20 as your initial starting point (excluding rake) .

So if you're a losing player , there is a 100% chance you will go bust at some point . However , it's not true that there is a 100% chance you will go bust after one month of playing .