How many three-letter “words” (strings of letters) can be formed using the 26 letters of the alphabet if repetition of letters (a) is allowed? (b) is not allowed?
asked Nov 23, 2016 in Word Problem Answers by HelpMe

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(a) Repetition is allowed. The letters A-Z can be used for each letter position so the maximum number of 3-letter words is 26*26*26=26^3=17576.

(b) Repetition is not allowed. The number of permutations of 3 different letters out of 26 letters is 26*25*24=15600.

answered Nov 24, 2016 by Rod Top Rated User (487,100 points)
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