compound probabilities

Question

A bag contains 33 blueblue marbles, 1010 yellowyellow marbles, 55 blackblack marbles. If one marble is drawn from the bag then replaced, what is the probability of drawing a blueblue marble then a blackblack marble?

Answer 1

total marbles = 1098

probability of blueblue = 33/1098

probability of blackblack = 55/1098

probability of blueblue and then a blackblack is 33/1098 x 55/1098 = 1815/1098^2