In short, your answer would be 80%, but let me provide you with explanation. This is a probability problem, and you are being asked to determine the probability that out of the total marbles you have, what is the chance you will pull one out that is not green? To begin, first find the total amount of marbles, which is 30. Then, subtract green from that total, which is what the problem is asking. That gives you 24, so you now know that 24/30 marbles are not green. Then, simply divide 24/30, which gives you 0.8, which allows you to determine your answer, which is 80%. I hope this helps, and let me know if you have any further questions!