Puzzle of the Day : 36
The game of Tic-Tac-Toe is played in a large square divided into nine small squares.
 Each of two players in turn places his or her mark – usually X or O _ in a small square.
 The player who first gets three marks in a horizontal, vertical and diagonal line wins.
 A player will always place his or her mark in a line that already contains (a) two of his or her own marks or (b) two of his or her opponent’s marks – giving (a) priority over (b)
Assume that both the players are intelligent enough.
1. Who will win the game, O or X?
2. Which was the sixth mark and at which position?
Source : The great book of Puzzles and Teasers