A bag contains 4 red marbles, 5 blue marbles and 3 green marbles. If two marbles are

drawn out of the bag, what is the exact probability that both marbles drawn will be

blue?

5/33

Step-by-step explanation:

There are a total of (4 + 5 + 3), or 12, marbles at the onset. The probability of drawing a blue marble then is 5/12. If on the first draw a blue marble comes up and is not replaced in the bag, then there are 4 remaining blue marbles out of 11 marbles, and so the probability of drawing a blue marble is 4/11.

Multiplying these two probabilities together, we get (5/12) (4/11) = 20/132, or 5/33.