6. (a) How many “words” of 4 different letters each can be made from the
letters A, E, I, O, R, S, T?
(b) How many of these words begin with a vowel and end with a
consonant?
(c) In how many of these words do vowels and consonants alternate?
7. (a) How many numbers of 5 different digits each can be formed from
the digits 0, 1, 2, 3, 4, 5, 6?
(b) How many of these numbers are even?
not zero
(c) How many of these numbers are divisable by 5?
verify this result