In the problem regarding 5 consecutive letters, make sure you are counting each term only once. For example, a careless method would have AAAAAABCDE counted twice (once for the first set of 5 A and once for the second set of 5 A)
In problem 40, how are you counting part a? I was doing 10 choose 5, but then I started thinking up other ways that seem like they could be right. Thoughts?
