Find the probability for the experiment of drawing two marbles at random (without replacement) from a bag containing four green, two yellow, and three red marbles. Both marbles are red.

Answer 1

There are a total of 9 marbles. On draw number 1, (since there are 3 reds and 9 total marbles) the probability of drawing a red is 3/9 or we can reduce that fraction to 1/3

On draw #2, since there are now 8 marbles in the bag and only 2 reds, the probability of drawing a red is 2/8 or we can reduce that fraction to 1/4.

The probability of both things happening is the multiplication of the two probabilities, so 1/3 x 1/4 = 1/12