The ratio given means that for every 2 white marbles, there are 5 blue marbles. That means that if you add 5 and 2, you get 7, which is the total in terms of the ratio. Now you know that there are more than 50 marbles in the bag, so the mutliple of 7 closest, and above, 50 is 56 (7 × 8). Therefore, the minimum number of marbles that can be in the bag is 56, hope this helps!
