Answer:
90%
Explanation:
Let x be the total number of matches,
Given,
80% of games were finished,
So, the number of finished games = 80% of x = 0.8x
∴ Remained games= x - 0.8x = 0.2x
Now, 40% of 80% of games were won,
So, the winning games in 0.8x matches = 40% of 0.8x
= 0.4 × 0.8x
= 0.32x
In order to finish games with the same number of wins as losses,
Winning percentage in all games must be 50%,
Thus, the total winning games = 50% of x = 0.5x
Let y be the winning percentage in 0.2x games,
So, the total winning games in 0.2x games = 
∵ Number of winning matches in 80% games + number of winning matches in 20% = total winning matches
⇒ 



Hence, the percent of winning the in the remaining games must be 90%.