10 marbles. 4 are green, 2 are red, and 4 are blue. choosing a marble at random, and without putting it back, chooses another one at random. what is the probability that both marbles he chooses are blue.

12/90 = 6/45

Step-by-step explanation:

In the first draw the probability will be 4/10 because there are 4 blue marbles and 10 total marbles. In the second draw, since they did not put the marble back, the probability will be out of 9 marbles. There is also only 3 marbles, so the probability will be 3/9. Since you are calculating the probability of both combined, the answer will be 4/10 * 3/9 = 12/90 which simplifies to 6/45