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Can you solve the counterfeit coin riddle? - Jennifer Lu

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3,596 Questions Answered

TEDEd Animation

Let’s Begin…

You’re the realm’s greatest mathematician, but ever since you criticized the Emperor’s tax laws, you’ve been locked in the dungeon. Luckily for you, one of the Emperor’s governors has been convicted of paying his taxes with a counterfeit coin, which has made its way into the treasury. Can you earn your freedom by finding the fake? Jennifer Lu shows how.

If you know the single counterfeit coin is lighter than the others, what is the maximum number of coins for which three weighs are guaranteed to reveal the counterfeit?

About TED-Ed Animations

TED-Ed Animations feature the words and ideas of educators brought to life by professional animators. Are you an educator or animator interested in creating a TED-Ed Animation? Nominate yourself here »

Meet The Creators

  • Educator Jennifer Lu
  • Director Outis
  • Script Editor Alex Gendler
  • Associate Producer Jessica Ruby
  • Content Producer Gerta Xhelo
  • Editorial Producer Alex Rosenthal
  • Narrator Addison Anderson

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