A bag contains 7 red marbles, 2 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?

Answer 1

The total number of marbles in the bag is 7 (red) + 2 (blue) + 3 (green) = 12 marbles.

The number of ways to choose 2 blue marbles out of 2 blue marbles is 2C2 = 1.

The total number of ways to choose 2 marbles out of 12 marbles is 12C2 = 66.

Therefore, the probability of drawing 2 blue marbles out of the bag is 1/66.