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Coins and a Balance Scale

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Author:Bennett Haselton
Description: You have twelve coins and a balance scale. One of the coins does not weigh the same as the other eleven, but you don't know if the odd coin is heavier or lighter than the others. How can you determine, in three weighings, which coin is the odd coin? With three weighings you can actually find the odd coin in a group of thirteen coins. However, you cannot determine whether the odd coin is heavier or lighter.

Levels: Middle School (6-8), High School (9-12)
Languages: English
Resource Types: Problems/Puzzles
Math Topics: Measurement

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