math 30-1 #1-2Permutations and combinations

1. Suppose a 3 letter code is to be made from the letters A, B, and C. a. List all the possible codes if a letter cannot be repeated. b. List all the possible codes if a letter can be repeated. C. Explain how the results from both a. and b. can be calculated without writing out all the possibilities. 2. Show that n! = ,P. What must 0! equal for the relationship to be true