How do I calculate this and what is the answer?

[Kyo]

So me and my friends were playing this game and there are 122 characters and we are on game mode that gives us 10 characters out of the 122 pool.
We need 3 specific characters out of the 122 in the 10 that is given out at a time.
How do I calculate this and what is the right answer so I can prove it myself also?

Thank you!

 

[Cubist]

Does the pool size decrease by one for every character that you get given?
Or, does the pool size always remain the same so that you could obtain, say, character number 1 (of 122) multiple times in your set of 10?

 

[Kyo]

Does the pool size decrease by one for every character that you get given?
Or, does the pool size always remain the same so that you could obtain, say, character number 1 (of 122) multiple times in your set of 10?

Yes it decreases.
So every game we are given a 10 character pool to pick from all of the 121 characters and we need 3 specific characters in those 10 given ones.

 

[Cubist]

Yes it decreases.

I think you're after the probability of getting all 3 specific characters. If so, then you'll need to use the hypergeometric distribution (click). Can you suggest suitable values for the variables N,K,n and k that will model your question?

Note, you'll need to decide whether the total number of characters available is 121 or 122 (since posts #1 and #3 give different amounts)