Answer:
Let the number of marbles in the large bag be L. Then we have: 25 : 7S = 7S : L Multiplying both sides by 7S, we get: 25(7S) = (7S)^2 : L 175S = 49S^2 : L L = (49S^2) / 175 L = (7S^2) / 25 Therefore, the number of marbles in the large bag is (7/25) times the number of marbles in the medium bag.