Jon S. answered • 12/02/20
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If repetition is allowed:
There are 10 possibilities for each for the 4 letters, so 10^4 total possible 4 letter words
If repetition is not allowed
There are 10 possibilities for the first letter, 9 for the second, 8 for the third and 8 for the fourth for 10 * 9 * 8 * 7 possibilities.
If the first letter must be A, then there is only 1 possibility for the first letter and 10 for the remaining 3 letters for 10^3 total possibilities.
Ember L.
This didnt actually take into account checking into a dictionary for true "words" versus patterns of characters
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04/16/21
Ember L.
I have this same question how many combinations of 01234 can I make 4 pattern combinations with repeats. I learn nCr and nPr probability but neither apply right? should I times digits by 4 so that I can emulate repetition? example (0,1,2,3,4,0,1,2,3,4,0,1,2,3,4,0,1,2,3,4) and use nPr but then I get permutations like "1111" and in those cases I have to subtract something. I think I might just brute force it.04/16/21