(12 points) Let X = (1,2,3,4,5).
(a) Find the number of sequences of length 7 over X.
(b) A palindrome of length kis a sequence aja2 ... 0 such that alk-1...0,01 = 0102 ...k-101ka Find the number of palindromes of length 7 over X.
(c) How many three digit odd positive integers with distinct digits can you write using only the numbers in X?