Question: Consider the word PEACH. We will make lists from the letters in PEACH, with repetition allowed.
(a) How many three-letter lists are there that don't begin with C, or don't end in P?
(b) How many four-letter lists are there in which the sequence of letters P, E, A appears in that order?
(c) How many three-letter lists are there in which the letters C, H appear consecutively?