Answer:
Hey there! So as you know, 3 out of 5 marbles are blue, which can be written as 3/5. To find the ratio of blue to yellow marbles, we need to find the number of yellow marbles.
We know that 5 marbles are blue and yellow combined, and 3 of them are blue, so that leaves 5-3 = 2 yellow marbles.
So the ratio of blue marbles to yellow marbles is 3:2, or 3/2. It means that for every 3 blue marbles, there are 2 yellow marbles.