There's nothing wrong with his probability unless you know for certain that somebody is only playing for a set amount of time. But since players play the game indefinitely, the number of ticks is going to be indefinite and you could just as well use infinity. As you get closer and closer to infinity, the variance will slim. And when you hit infinity, it will disappear. So with an infinite number of ticks, each piece of equipment will break once every 25 minutes. But that is ignoring wpf. Somebody mentioned wpf, but that's too much variability to get into.
For the record, I finished college with an engineering degree, which means I took Probability & Statistics as well as a crapload of other math classes.
It works on a per-round basis, though. Then it resets.
A round probably lasts 3-5 ticks during which you can only be affected by a damaged item roll a maximum of once per item.
If a round lasts 5 ticks and a specific item fails each of the 5 rolls, you only pay once. After a new round starts, the fail chance counts again.
Also, if you want to consider an infinite number of ticks, you have an infinite amount of gold and the entire model breaks down completely. You need to look at it one round at a time to make the model practical, and 5 doesn't really come that close to infinity.
After the bragging about your degree, I can't tell if you're a very convincing troll or if you're serious.
yea but my Equip is 25000 and I am constantly losing money 
and the dude I play with got equip with 83k and lose like nothing. some kind of bug? idk. 
It helps to build up a nest egg. The amount of gold you're making at a given time can vary depending on how lucky you are with team wins and with chance of needing to repair. Build up a little bit of buffer and you will have some room to dip down a few thousand without it being a problem. You'll make up for it later when your luck turns. You should be making money pretty quickly with only 25k in gear, but there will be fluctuations.
