A Gallon of Water

In this puzzle you need to carefully read the label on the water bottle.

This bottle of water was purchased in a market in New York City. What’s wrong with the label?

Course:

Math [1]

Result/Solution(s)

The label says, “NET WT. 1 GAL,” which is an abbreviation for “Net Weight 1 Gallon.” The label is saying that the weight of the water is 1 gal.

The problem is that the gallon is a unit of volume, not weight.

The gallon is a measure used in the United States. Its metric equivalent is 3.78 L, which is also on the label.

But the mistake is not completely off the mark. Knowing that you have 1 gal of water also tells you what it weighs. As the label says, a gallon is equal to 128 fluid oz. A fluid ounce is a measure of volume, like the gallon. But there is a unit of weight called an “ounce” that is the weight of 1 fluid oz of water. So the water weighs 128 oz, or 8 lbs. (There are 16 oz in a pound).

Math Puzzle [2]