Answer: There is 12 servings of lemon juice needed for 36 cups of water.
Explanation:
Since we have given that
Number of cups of water to make lemonade = 36
Ratio of lemon juice to water = 1 : 3
So, number of lemon juice cups be x
number of cups of water be 3x.
According to question, it becomes,

Hence, there is 12 servings of lemon juice needed for 36 cups of water.