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Can you solve the risky disk riddle? - James Tanton

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TEDEd Animation

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Your antivirus squad is up against a code that’s hijacked your mainframe. What you’ve learned from other infected systems, right before they went dark, is that it likes to toy with antivirus agents in a very peculiar way— and you’re the agent that’s been selected to go up against the malware. Can you figure out which disk that runs your mainframe has been corrupted? James Tanton shows how.

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Consider the version of the puzzle based on eight discs rather four. Number the discs as three-digit binary codes: 000, 001, …, 111. You enter the mainframe and see discs 010, 011, 101, 111 are switched on. You are told that disc 110 is corrupted. Which disc do you switch to communicate this disc number to the squad?

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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 James Tanton
  • Director Igor Coric, Artrake Studio
  • Music Cem Misirlioglu
  • Sound Designer Cem Misirlioglu
  • Director of Production Gerta Xhelo
  • Editorial Director Alex Rosenthal
  • Producer Bethany Cutmore-Scott
  • Narrator Addison Anderson

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