Help With This Permutation/commutation Problem?
Published on Wednesday, February 17, 2010 
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Companies whose stocks are listed on the New York Stock Exchange (NYSE) have their company name represented by either 1, 2, or 3 letters (repetition of letters is allowed). What is the maximum number of companies that can be listed on the NYSE?
Can you also explain how to do it?
1 Comment
Comment by MathMan TG
Answer 26 + (26 * 26) + (26 * 26 * 26) = 26 + 676 + 17576 = 18278
One letter id’s: 26 possibilities A, B, C, etc.
Two letter id’s:
26 choices for the first letter and for each one 26 choices for the second letter, so 26 * 26
Same principle for three letters.
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