Answer: 9:7
Subtract 32 by 14, because there are 14 red marbles.
32 - 14 = 18.
Now, get the numbers 14 and 18. Reduce them to the lowest.
18 ÷ 2 = 9
14 ÷ 2 = 7
Make 9 & 7 to a ration.
Ration- 9:7
================================================
Explanation
There are 32 marbles and 14 are red. If there are only two colors, then we have 32-14 = 18 blue marbles.
The ratio of blue to red is 18:14. We write the two values separated by a colon. The order matters (blue comes first, then red).
The last step is to reduce the ratio 18:14 to 9:7. Note how I divided both parts by the GCF 2.