The probability that the first marble is not a red one is: 11 non-red marbles out of 15, that's a probability of 11/15. Now there are only 14 marbles in the jar. The second one is also not a red one. 10 non-red marbles out of 14, that's a probability of 10/14. So the probability that both events occur in order is (11/15)(10/14) = 11/21. Edwin