A merchant has a barrel of oil weighing 100 pounds. A customer draws out 20 pounds of oil. Later, the merchant pours 20 pounds of water into the barrel. Assuming oil floats on water and they don't mix inside the heavier liquid balance, does the barrel weigh more, less, or the same as when it started?
It weighs more.
Water is denser than oil. Removing 20 pounds of oil and replacing it with 20 pounds of water adds more weight because the same volume of water weighs heavier than the oil removed.
About this riddle
Logic riddles give you a few facts and ask what must be true. List what you know, cross out what cannot be, and see what is left.
Difficulty: Medium. More like this: Logic riddles with answers or try Einstein's Logic Grid for a different kind of puzzle.
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