What was the question for this implicit rationale, and corresponding answer?
He drinks 128 / 2 = 64 ounces of coffee every 4 days. That means he drinks 64 / 4 = 16 ounces of coffee a day. So he drinks 16 / 8 = 2 cups a day.
 The answer: 2
The question: John buys 1/2 gallon jugs of cold brew coffee every 4 days. How many cups of coffee does he drink a day?