Final answer:
For every cup of lemon juice, you will need 2 cups of water.
Step-by-step explanation:
The equation j = 2w describes the relationship between the number of cups of water, w, and the number of cups of lemon juice, j, used in the recipe. This equation tells us that for every cup of lemon juice, we need 2 cups of water.
For example, if we have 3 cups of lemon juice, we would need:
2 cups of water * 3 cups of lemon juice = 6 cups of water.
Therefore, for each cup of lemon juice, we need 2 cups of water.