There are 19 marbles in a bowl, 5 of which are yellow. The remainder are split into blue marbles and red marbles in the ratio 3:4 respectively. How many more red marbles than yellow marbles are there? Let's think first. Chain of thought:
5 out of 19 marbles are yellow so the remainder which is 19 - 5 = 14 marbles are blue and red. 14 marbles are split into blue and red in the ratio 3:4 so each "share" is 14 / (3 + 4) = 2 marbles. There are 4 "shares" of red marbles which totals to 4 * 2 = 8 red marbles. There are 8 - 5 = 3 more red marbles than yellow marbles.
Therefore, the answer is 3.