Joe wants to find all the four-letter words that begin and end with the same letter, and this letter does not appear in the middle. How many combinations of letters must he examine? A word is any sequence of letters, such as MTHM, and does not have to be English. (You can use a calculator for this problem.)

 Apr 24, 2022

We have   26 ways of choosing the beginning letter   and  by default the last letter is the same

And the middle two letters can be  any one of the 25 remaining letters....so


26 * 25 * 25   =    16,250 possible "words "



cool cool cool

 Apr 24, 2022

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