Answer:
In the bag there are 14 marbles, of which 6 are green, and 8 yellow. Marco, the first to take a marble, has 6/14 chances to take a green marble, while Katlynn, in case Marco had grabbed a green one, would have 5/13 possibilities.
So, if Marco has 6/14 possibilities, the percentage probability of taking a green marble would be 42.8%. In turn, Katlynn would have 5/13, that is, her individual probability would be 38.4%.
To obtain the probability that both obtain a green marble, we must combine both results: 0.428 x 0.384 = 0.359. That is, the probability arises from the multiplication between both results (42.8% x 38.4%). The final result is that the probability of both obtaining a green marble is 35.9%.