Question

If only half as much milk is used each day, after how many days will more milk need to be purchased?

Answer 1

If you are using half as much milk every day, you'll never run out because you'll just keep using half as much. You still won't run out with the coffee shop problem or the refrigerator problem.

Answer 2

If you are taking half each time you will never finish it, therefore you will never have to purchase more milk. (: