Answer: The ratios is 1 to 3.
Step-by-step explanation: First you have to find how many comedy DVDs there are which in this case is 12. Then, you find the total number of DVDs by finding what 12+15+9 equals. It equals 36. So the ratios is 12 to 36. You can simplify this by dividing both sides by 12 and you get the ratio of 1 to 3.