October 7, 2014

Problem of the Week

for Tuesday, Oct. 7, 2014

A game of tic-tac-toe is played on the standard three by three board. The first to get three in a row of the same symbol (either x or o) wins the game. There is one rule change, however. When it is your turn, you may mark either an x or an o in an empty square and you can make a different choice each time its your turn. What strategy can you use to ensure that you will win every game you play? Do you need to go first or second to execute this strategy?

Winners of the tic-tac-toe game