Tic Tac Toe(only one mark is given)

Logic Level 1

If it's O's turn now, where should O put the mark to draw the match?

Assume that both are playing optimally.

1 2 3 4 5 6 7 8

1 solution

X X
May 6, 2018

Put on 1, $\rightarrow$ 7 $\rightarrow$ 8 $\rightarrow$ 5 $\rightarrow$ 2 or 3,lose.

Put on 2, $\rightarrow$ 1 $\rightarrow$ 4 $\rightarrow$ 5 $\rightarrow$ 3 or 8,lose.

Put on 3, $\rightarrow$ 8 $\rightarrow$ 7 $\rightarrow$ 1 $\rightarrow$ 4 or 5,lose.

Put on 4, $\rightarrow$ 8 $\rightarrow$ 7 $\rightarrow$ 5 $\rightarrow$ 1 or 3,lose.

Put on 6,7,8 is as same as 2,4,1,lose,so we can only put on 5.