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# how many of letters is allowed or is not allowed?

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How many six-letter "words" (strings of letters) can be formed using the 26 letters of the alphabet if repetition of letters is allowed or is not allowed?

May 12, 2020

#1
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If we have repeat-ok,

then it's 26^6 since there's 26 letters to pick from for each.

If not...

We have 26*25*24*23*22*21

SINCE it's 26 letters for first, 26-1 because one is taken, etc

If you don't understand anything feel free to ask.

May 12, 2020
#2
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How many six-letter "words" (strings of letters) can be formed using the 26 letters of the alphabet if repetition of letters is allowed or is not allowed?

If the order or position of the letters is NOT important, such as:MASFLD, which is just a "string" of 6 letters, then it is a "combination" and NOT a "permutation" problem.

1 - With repeats allowed, then you should have:
[26 + 6 - 1] C 6 =31 C 6 =736,281 combinations.

2 - With repeats not allowed, then it is simply:
26 C 6 =230,230 combinations.

May 12, 2020