Question

Suppose a jar contains 11 red marbles and

21 blue marbles. If you reach in the jar and
pull out 2 marbles at random at the same
time, find the probability that both are red.

Answer 1

There are 32 marbles. 11 are red. So odds of a red on the first are 11/32.

Now there are 31 marbles left. 10 are red. So odds of a red on the second is 10/31.

Probability both are red, just multiply …. 11/32x 10/31 = 110/992 or 0.111.