Answer: If you want to make more cookies then what is called for in this situation then you would need 6 cups of milk.
Step-by-step explanation: You have 2 cups of milk and 3 cups of flour of course. In order to make a complete batch you need 2 cups of milk and 3 cups of flour. In order to make a second batch you need the same things as you did for the first batch. Therefore two batches of cookies requires 4 cups of milk and 6 cups of flour. In this situation you want to make 3 batches of cookies. The required items are 6 cups of milk and 9 cups of flour.