A jar has 10 marbles and 4 of them are green. You pull 3 marbles without replacement. What is the probability that all are green? Write your answer as a fraction. You do not need to simplify.

Answer 1

The probability of pulling a green marble on the first draw is 4/10 or 2/5.
After the first green marble is drawn, there are 3 green marbles left and 9 marbles total.
So the probability of pulling a green marble on the second draw is 3/9 or 1/3.
After the second green marble is drawn, there are 2 green marbles left and 8 marbles total.
So the probability of pulling a green marble on the third draw is 2/8 or 1/4.

Therefore, the probability of pulling all 3 green marbles is (2/5) * (1/3) * (1/4) = 2/60 = 1/30.