Math 2602  B1, B2                                                                                    Homework  #4
                                           Due Thursday, September 16, 2004


1. How many of the words of length 16, which can be formed using the alphabet { A , C , G , T }, have

    i)     exactly two A's ?

    ii)    at least two A's ?

    iii)   exactly one A and exactly one C ?

    iv)   exactly one A or exactly one C ( or both ) ?