A bag contains 4 red marbles and 6 blue marbles. If two marbles are drawn at random without replacement, what is the probability that both marbles are blue?

✓ Correct Answer: Option D

The probability of drawing the first blue marble is 6/10. After one blue marble is drawn, there are 5 blue marbles left out of 9 total. The probability of drawing a second blue marble is 5/9. So, (6/10) * (5/9) = 30/90 = 1/3.