0.01% for the Cosmic Wings is what Raxxanterax claims a dev told him. Whether or not that’s true, I don’t know. I can only base the odds on numbers given.
Until that number came up, I was going to farm the wings, as were many other people I’m sure.
As far as the numbers go for players them, it’s pretty basic math.
But it’s sometimes easier to work backwards.
Let’s say you roll a die.
1 in 6 odds.
What are the odds of it not coming up with 6:
- once: 5 in 6
- twice in a row: (5/6)2
- three times in a row: (5/6)3
- …
So the odds you hit 6 at least once is 1 - (Pn) where P is the probability of the event not happening, and n is the number of trials. In this case, 1 - ((5/6)3) = 0.42 or a 42% chance of getting 6 at least once.
Now, let’s take the event. With a 0.01% drop rate, there is a 99.99% chance of the event not happening, so P is 0.9999. The number of trials I stated for a 50% chance is 6931.
1 - (0.99996931) = 0.5, so a 50% chance of the event occurring.
So, now, we want to find the number of attempts required of something happening at a given probability.
The odds it doesn’t occur is 99.99%, so the odds of it not happening once is 0.99991, not happening twice is 0.99992, etc.
We want to be 50% sure here, so we’re looking for the smallest value of n, where 0.9999n < 0.5.
This becomes
n * log(0.9999) < log(0.5)
n = log(0.5) / log(0.9999)
This also can become simplified to log (base of event not happening) of (the odds we’re after). Or, in this case, log0.9999(0.5).
So n = 6931.125…
Technically, it’s 6932, since we need the ceiling here, but I just rounded to the closest number.
Like I said in the post, no one ever realistically puts up perfect efficiency. And you’re not going to have 7000 ancient puzzle rings nor are you probably going to have 7000 Greater Rift keys ready. Throw in opening times, close times, real life occurring which requires you to step away for a few minutes, etc.
Now, hopefully he just misheard, because I’d have to estimate that to get a 50% chance, you probably need to realistically put in roughly 15 hours a day, every day of the event.
Let’s say you play an average of 2 hours a day, getting 15 gifts an hour. You’ll have 1300 gifts total. That’s about a 12% chance of getting the wings. Now, certainly some people will get them. Perhaps a few will get them in under 10 attempts. But unless the percentage they stated is wrong, getting the Cosmic Wings in the event is just going to be about sheer luck.