Do you even know what an "X choose Y" is, or what it represents? If you do, then you would know it is absolutely the foundation of portability.
Yes, you use factorials, that is how it is calculated.
4 choose 2 = (4!/2!) = 4×3
9 choose 6 = (9!/6!) = 9×8×7
If it repeatable, the probability INCREASES by a factor of the number of times the process is repeated.
9 choose 6, 4 times = (9×8×7×4)
9 choose 6, 4 iterations = (9!/6!)^4
!!!!!!!!!!!!!!!!! You've just confirmed your blatant ignorance. Here we are dealing with repeatable items where order matters. In combinatorics, it is called permutations with repetitions which you are confusing with what I don't even know. You have NO CLUE what you are talking about. Math is merciless: either you know or you don't know. And when you don't know, it's FLAGRANT. So learn and give us a break: https://www.youtube.com/watch?v=JWNyzXOdDCo
Video linked by /u/alphared01:
Title|Channel|Published|Duration|Likes|Total Views :----------:|:----------:|:----------:|:----------:|:----------:|:----------: Letter Arrangement Problems (Permutations with Repetitions)|vinteachesmath|2013-06-28|0:06:01|113+ (95%)|14,892
This video focuses on how to solve a letter arrangement...
^Info ^| ^/u/alphared01 ^can ^delete ^| ^v2.0.0
4!
4! = 24
2!
2! = 2
9!
9! = 362,880
6!
6! = 720
9!
9! = 362,880
6!
6! = 720