Probability (Add and Mult)

1.

a. A bag contains 44 greengreen marbles, 99 yellowyellow marbles, and33 blackblack marbles. If a marble is drawn from the bag, replaced, and another marble is drawn, what is the probability of drawing first a greengreen marble and then a blackblack marble?

b. A bag contains 99 redred marbles, 33 blackblack marbles, and44 yellowyellow marbles.If two different marbles aredrawn from the bag , what is the probability of drawing first a redred marble and then a yellowyellow marble?