Question

Joe wants to find all the four-letter words that begin and end with the same letter. 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.

Answer 1

There are 17,576 combinations.

There are 26 letters to choose from for the first letter; 26 for the second letter; 26 for the third letter; and 1 for the last letter (it must be the same as the first letter).  This gives us

26*26*26*1 = 17576