How many different 7-letter words can be made a. if the first letter must be B, W, P, or N and no letter may be repeated? b. if repeats are allowed (but the first letter is B, W, P, or N)? c. How many of the 7-letter words (starting with B, W, P, or N) with no repeats end in H? a. If the first letter must be B, W, P, or N, and all the letters in the word must be different, then there are 7-letter words