1. Convert to the same unit:

* Since 1 gallon equals 4 quarts, we can convert 9 gallons to quarts: 9 gallons * 4 quarts/gallon = 36 quarts

2. Express the ratio:

* The ratio is now 36 quarts : 48 quarts.

* You can simplify this ratio by dividing both sides by their greatest common factor (12): 36/12 : 48/12 = 3:4

Therefore, the ratio of 9 gallons to 48 quarts is 3:4.