Chess Tournament Problem In a chess tournament, \( n \) men and 2 women participated. Each player plays 2 games against every other player. Additionally, the total number of games played among the men exceeded by 66 the number of games that the men played against the women. Find the total number of players in the tournament.
Step-by-step Solution:
We are given that \( n \) men and 2 women participated in a chess tournament. Each player plays 2 games against every other player. Our goal is to determine the total number of players.
Step 1: Calculate the Total Games Played Among Men
The number of ways to choose 2 men from \( n \) men is:
\[
\binom{n}{2} = \frac{n(n-1)}{2}
\]
Since each pair plays 2 games, the total number of games played among the men is:
\[
G_m = 2 \times \frac{n(n-1)}{2} = n(n-1)
\]
Step 2: Calculate the Total Games Played Between Men and Women
Each of the \( n \) men plays 2 games against each of the 2 women. So, the total number of games played between men and women is:
\[
G_{mw} = 2 \times n \times 2 = 4n
\]
Step 3: Use the Given Condition
We are given that the games played among men exceeded the games played between men and women by 66:
\[
n(n-1) = 4n + 66
\]
Step 4: Solve for \( n \)
Rearrange the equation:
\[
n^2 - n = 4n + 66
\]
\[
n^2 - 5n - 66 = 0
\]
Solve the quadratic equation:
\[
n = \frac{-(-5) \pm \sqrt{(-5)^2 - 4(1)(-66)}}{2(1)}
\]
\[
n = \frac{5 \pm \sqrt{25 + 264}}{2}
\]
\[
n = \frac{5 \pm \sqrt{289}}{2}
\]
\[
n = \frac{5 \pm 17}{2}
\]
\[
n = \frac{5 + 17}{2} = \frac{22}{2} = 11 \quad \text{or} \quad n = \frac{5 - 17}{2} = \frac{-12}{2} = -6
\]
Since \( n \) must be positive, we take \( n = 11 \).
Step 5: Find the Total Number of Players
The total number of players in the tournament is:
\[
n + 2 = 11 + 2 = 13
\]
Final Answer:
\(
{13}
\)