/jp/ - Otaku Culture

>>40295082
Simple
Rolling a character in X attempts can be reworded as failing trying to not get them X times in a row.
It sounds confusing, but it's basically explaining how to get your chance of success, you take the chance of every attempt failing and invert it.
So in our case in order to find the chance of succeeding a 0.5% roll over 180 attempts is
1 - 0.995^180
Which is basically saying you have a 41% chance to fail