Question

A bag contain 5 red marbles, 4 blue marbles and 6 green marbles. If three marbles are drawn out of the bag, what is the exact probability that all three marbles drawn will be red?

Answer 1

2/91.

Explanation:

There are 15 marbles in the bag.

Prob(First draw is red) = 5/15 = 1/3.

Prob(Second draw is red) = 4/14 = 2/7.

Prob(Third draw is red) = 3/13.

So probability that all 3 are red = .1/3 * 2/7 * 3/13

= 6/273

= 2/91.