You have a barrel of oil weighing 100 pounds. You pour out half of the oil, and the barrel now weighs 60 pounds. What is the weight of the empty barrel?
20 pounds
Half of the oil weighs 100 - 60 = 40 pounds. Therefore, the full barrel of oil contains 80 pounds of oil. Subtracting this from the total initial weight of 100 pounds leaves 20 pounds for the barrel.
About this riddle
Math riddles hide a calculation inside a short story. Pull out the numbers, work out what is being asked, and watch for a trick such as a unit change.
Difficulty: Medium. More like this: Math riddles with answers or try Target 24 for a different kind of puzzle.
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