Consider all 6-letter "words" (string of 6 letters in a row) that can be made from the eight letters a through h.
(a) How many of these words are there total?
(b) How many of these words contain no repeated letters?
(c) How many of these words (repeated letters allowed ) start with the sub- word "aha"?
(d) How many of these words (repeated letters allowed) either start with " aha" or end with "bah" or both? Explain your counting method.