Math 2602  A1 - A3                                                                                Homework  #4
                                           Due Thursday, September 22, 2005


How many of the words of length 8 which can be formed using the alphabet { A , C , G , T } have

    i)  exactly 3 A's ?

   ii)  at most  2 A's ?

  iii)  at most one A and at most one C ?

   iv)  at most one A and at least one C ?