[Question]: A jug is filled with 5 liters of water and a bucket is filled with 4 jugs. How many liters of water are contained in 2 buckets?
[Answer]: 4 jugs contain 4 * 5 = 20 liters of water. 2 bucket contains 20 * 2 = 40 liters of water.
So the answer is 40.

[Question]: John has a very inefficient toilet that uses 5 gallons of water per flush and his household flushed 15 times per day. He replaced it with a toilet that uses 80% less water per flush. How much water did John save in June?
[Answer]: He used to use 5 * 15 = 75 gallons of water per day. This means he used 75 * 30 = 2250 gallons a month. His new toilet uses 5 * .8 = 4 gallons less water per flush. So, it only uses 5 - 4 = 1 gallon per flush. That means he uses 1 * 15 = 15 gallons per day. All in all, it accounts for a total usage of 15 * 30 = 450 gallons. So, he saved 2250 - 450 = 1800 gallons per month.
So the answer is 1800.

[Question]: John buys 1/2 gallon jugs of cold brew coffee every 4 days. How many cups of coffee does he drink a day?
[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.
So the answer is 2.