Flip This

A magician shows four fair coins. One is two-headed; the others have both heads and tails.
He places the coins in a black bag and blindly removes one. Repeated flips of the selected coin show “heads”.
After how many flips is it safe to bet with even odds that the selected coin has two heads?

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October 30th, 2010 | Category: Brain Riddle, Mathematical, Real Life, Science Riddles |  Email This Riddle

6 guesses to Flip This

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• Tiffy

  March 28, 2011 at 1:24 AM

  One?

• Dude

  March 29, 2011 at 7:40 AM

  Nope, that’s not it. Keep trying.

• Eva

  July 4, 2011 at 12:30 AM

  13?

• Dude

  July 4, 2011 at 5:50 AM

  Nope, keep trying.

• Victoria

  June 4, 2015 at 5:26 PM

  3?

• Dude

  June 7, 2015 at 6:59 PM

  Victoria, you are correct!
  It must be 3.