Porcellio Card ??

[GM-Ayu]

A little excursion into probabilities:

A probability is the rate at which an Event will occur. It is a number between 0 and 1. (Yes 1% is just another way to write 1/100 or 0.01)
For every event there is the contrary event, that will take place every time the Event hasn't taken place. Let's call the Event E and the contrary event C.
Of course the probablities of all things that can happen add up to 1. This comes from "nothing happening" being the contrary event to "anything happening". Now the chance for an event to occur is p(E), the chance of the contrary is 1-p(E) = p©.
If you repeat the experiment, the chance an event occurs multiple times is p(E) ^ x where x is the number of times you repeated the experiment. If you have 50% chance of hitting and you strike twice your chance to hit BOTH TIMES is 0.5 ^2 = 0.25 = 1/4. Now let's assume you have a 20% chance to score a crit. Critting every strike in a row of 5 would be 0.2 ^5 = 0.00032 = 0,032%. The chance to crit AT LEAST ONCE in those 5 strikes is the contrary to not critting a single time. Not to crit has 80% chance of happening. So the cance not to crit in 5 strikes is 32.768% (it's 0.8 ^5, because 1-0.2 = 0.8 is the chance not to crit and you repeated the experiment five times). The chance to crit at least once is 1-32.768% = 67.232 %.
For cards it's 0.03% = 0,0003. So the chance not to find a card in a monster you kill is 99.97%. If you kill X monsters the chance not to find any cards is 0.9997 ^X. The chance to find at least one card is the contrary of that so it's 1-0.9997^X. Or 1- (1-0.0003)^X.
Of course the chance to find the card in this specific monster still is 0.03%, but killing lots of them will increase your chance of finding one. If this weren't so, farming cards would become about impossible...

I hope this was understandable...


Btw.??A ^B is "A to the power of B" it's A multiplied B times with itself. 2^3 is 2*2*2 = 8.

The only incorrect part is the bolded part. Chance of finding a card is independent event. Just because you killed 15000 monster already, that doesn't push the chance of the 15001st monster to have an extremely high chance of a card. It's still going to be 0.03% of a card. You can't "trick" probability to kill 3000 normal monsters, and then go "oh yeah my chance of finding a card is now up to 30%+, I'll strictly fight mvp now to boost drop rate!"

The formula vanadis provided only helps you summarize the probability of what you have done in the past from happening. It doesn't predict the future of *when* do you get a card. This formula is only effective for theorycrafting, and analyzing the past, and is completely irrelevant to what happens in the future.