Futility Closet

Galton’s Paradox

Posted in Science & Math by Greg Ross on May 30th, 2008

http://en.wikipedia.org/wiki/Image:2005-Penny-Uncirculated-Obverse-cropped.png

Suppose you flip three fair coins.

Necessarily two will match, and it's an even chance whether the third will be head or tail.

Therefore the chance that all three will match is 1/2.