5. Alec has won $49 \%$ of the 200 games of chess he has played. He would like to have won exactly $50 \%$ of his games. What is the smallest number of extra games he needs to play?
A 0
B 1
C 2
D 3
E 4
Solution
$\mathbf{E}$

Winning $49 \%$ of 200 games means winning 98 games and not winning 102. For Alec to have equal number of wins and not-wins he needs to win $102-98$ games, that is 4 games. This will mean that he will have 102 wins out of 204 making a $50 \%$ rate of success.