We love a good brain teaser and this one will surely challenge you. This riddle is courtesy of Alex Gendler in his TED-Ed lesson that explains the “prisoner hat puzzle.”
In this puzzle, you and nine other people have been abducted by aliens. The aliens are going to eat you, but if you can prove you are intelligent, then they will spare your lives. To figure out if you are intelligent, the aliens came up with a challenge for you to figure out.
- The ten people are asked to line-up in a single file line in order of tallest to shortest so that each person can see all the shorter people in front of them.
- Black or white hats are randomly placed on each person and you can only see the hats of the people in front of you.
- You cannot see your hat or the hat of the person behind you.
- Starting with the tallest person (and moving to the shortest person), each person can only say “black” or “white” to guess the color of his or her hat.
- You cannot say anything else. You are allowed one wrong guess, meaning one of the 10 people can be wrong.
The good news is that you can talk as a group to come up with a plan before you start.
Good luck. The answer to the puzzle starts at 1:40 into the video below.