User blog:ReddUT/How to calculate probability of obtaining something you want from Top 50 decoders.

Math warning.
First, you need to know the probabilities from one decoder. Then, you need to know the probability of you not obtaining it, which is easy.

All Top 50 Unlimited Decoder premium chances are 1%. That includes Top 50 Unlimited Premium. Thus, it's easy to figure something's probability out. If something has x8, I'll use Blade Runebreaker as an example, as it was x8 in CSNZ.

1% times 8 is 8%. Now, the probability of not obtaining it in one decoder is 92%. Convert this to a decimal ranging from 0 to 1 where 0 is 100% chance to obtain from one decoder and 1 is 0% chance to obtain from one decoder. In this case, 0.92.

Now, figure out how many decoders you want to open. Try to balance price, unless you're like me, in which case, who cares how much :v

I'll use 40 as an example. Raise your number from before, 0.92, to 40. So the operation would be 0.92^40. Because we, as human beings, are not supercomputers, just google it. It'll do it for you.

0.92^40 = 0.035605... Move the decimal point two spaces to the right. 3.56% chance of you not obtaining Blade Runebreaker in 40 Top 50 Unlimited Premium decoders.

Now for something like Red Dragon Cannon in CSNZ, which is x3 atm, would be 0.97, 97% chance of not obtaining in one decoder.

Performing the operation again, using 40 as the number of decoders again, we get this.

0.97^40 = 0.295712... 29.5% chance of not obtaining.

That's about it. For Top 50 Regular decoders, the chances are 0.15% by default. x8 is 1.2%, and x3 is 0.45%, from one decoder. For normal, it would be 0.9985. 99.85% chance of not obtaining it. x8 is 0.988, and x3 is 0.9955.

I hope this isn't confusing. Just trying to help people decide what risks to take.

Source of the percentages: CSO Korea's site itself.