Good effort Rampager but there are MORE than 20 marbles in the bag.
2+3=5
so the mables have to be divisable by 5
So there are 5n marbles in the bag where n is and integer greater than 4
number of whit ones = 2/5 * 5n = 2n
number of blue ones = 3/5 * 5n = 3n