(a)    =  = 5*9 = 45  ways.      ANSWER



(b)   6*4 = 24  ways.                     ANSWER



(c)   It can be computed in 2 ways.


          1)  Having the numbers from (a) and (b), everybody can easily conclude 

              that the answer for (c)  is the difference  45 - 24 = 21  ways.



          2)  Another way to compute it is this :    +  = 15 + 6 = 21.

              Surely, it gives the same answer.

     When I solve a problem for you, I expect to get your "THANKS" back.


     It is the simple and standard way to let me know that you are an educated person.


     Otherwise, I will think that I work for idiots.