Question

You are going to mix a gallon bucket of window cleaner. The instructions direct you to mix 1 part cleaner to 3 parts water. How much cleaning solution will you need to use?*

Answer 1

You have a bucket 1 gallon big.
To mix cleaner and water you need to divide the bucket's capacity into 4.
It's easy in this case as gallon is divided into quarts (1 gallon = 4 quarts).
We know that one part will be cleaner, it means that you will need to use 1 quart of the cleaner.