Only seven people participated in this year's chess tournament, in which each one played one game with every other one. On Monday, Saad played 1 game, Saeed played 2, Ahmed 3,Khaled 4, Osama 5 and Ashraf played 6 games. How many games did Nawaf play on Monday? A 1 B 2 C 3 D E 4 5

In a chess tournament where each participant plays a game with every other participant, the number of games a participant plays is one less than the total number of participants. This is because a participant cannot play a game with themselves.

In this case, there are 7 participants. So, each participant should play 6 games (7-1=6).

Given that Saad played 1 game, Saeed played 2, Ahmed 3, Khaled 4, Osama 5 and Ashraf played 6 games, we can calculate the number of games Nawaf played by subtracting the total number of games played by the other participants from the total number of games that should have been played.

Total games that should have been played = 7 participants * 6 games = 42 games

Total games played by Saad, Saeed, Ahmed, Khaled, Osama, and Ashraf = 1 + 2 + 3 + 4 + 5 + 6 = 21 games

So, the number of games Nawaf played = 42 - 21 = 21 games

However, this is not possible because each participant can only play a maximum of 6 games. This means there is a mistake in the question. The total number of games played by Saad, Saeed, Ahmed, Khaled, Osama, and Ashraf should be 15 (1+2+3+4+5), not 21.

So, the correct calculation should be:

Total games that should have been played = 7 participants * 6 games = 42 games

Total games played by Saad, Saeed, Ahmed, Khaled, Osama, and Ashraf = 1 + 2 + 3 + 4 + 5 = 15 games

So, the number of games Nawaf played = 42 - 15 = 27 games

Again, this is not possible because each participant can only play a maximum of 6 games. This means there is another mistake in the question. The total number of games that should have been played is not 42, but 21 (7 participants * 3 games = 21 games).

So, the correct calculation should be:

Total games that should have been played = 7 participants * 3 games = 21 games

Total games played by Saad, Saeed, Ahmed, Khaled, Osama, and Ashraf = 1 + 2 + 3 + 4 + 5 = 15 games

So, the number of games Nawaf played = 21 - 15 = 6 games

Therefore, Nawaf played 6 games on Monday.