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A chess match between two players A and ...

A chess match between two players `A` and `B` is won by whoever first wins a total of two games. Probability of `A's` winning, drawng and losing any particular game are `1/6, 1/3` and `1/2` respectively. (The game are independent). If the probability that `B` wins the match in the `4^(th)` gams is `p`, then `6p` is equal to

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To solve the problem, we need to find the probability \( p \) that player \( B \) wins the match in the 4th game. The match is won by the first player to win 2 games. ### Step-by-step Solution: 1. **Understanding the Game Structure**: - Player \( A \) can win, draw, or lose a game with probabilities: - \( P(A \text{ wins}) = \frac{1}{6} \) - \( P(\text{Draw}) = \frac{1}{3} \) - \( P(B \text{ wins}) = \frac{1}{2} \) Since the game can end in a draw, we need to consider the scenarios where \( B \) wins the match in the 4th game. 2. **Possible Scenarios for \( B \) to Win in the 4th Game**: - For \( B \) to win in the 4th game, the following scenarios can occur: - \( A \) wins 1 game, \( B \) wins 1 game, and the other 2 games are draws. - \( B \) wins 2 games and \( A \) wins 1 game (not possible since we need \( B \) to win in the 4th game). The valid sequence of outcomes for \( B \) to win in the 4th game can be: - \( A, B, D, B \) - \( D, A, B, B \) - \( B, D, A, B \) - \( D, D, A, B \) - \( D, B, D, B \) 3. **Calculating the Probability**: - The probability that \( B \) wins in the 4th game can be calculated as follows: - Let’s denote: - \( W_A = \frac{1}{6} \) (A wins) - \( W_B = \frac{1}{2} \) (B wins) - \( D = \frac{1}{3} \) (Draw) The probability that \( B \) wins in the 4th game can be calculated by considering the valid sequences: - For the sequence \( A, B, D, B \): \[ P(A, B, D, B) = W_A \cdot W_B \cdot D \cdot W_B = \frac{1}{6} \cdot \frac{1}{2} \cdot \frac{1}{3} \cdot \frac{1}{2} = \frac{1}{72} \] - For the sequence \( D, A, B, B \): \[ P(D, A, B, B) = D \cdot W_A \cdot W_B \cdot W_B = \frac{1}{3} \cdot \frac{1}{6} \cdot \frac{1}{2} \cdot \frac{1}{2} = \frac{1}{72} \] - For the sequence \( B, D, A, B \): \[ P(B, D, A, B) = W_B \cdot D \cdot W_A \cdot W_B = \frac{1}{2} \cdot \frac{1}{3} \cdot \frac{1}{6} \cdot \frac{1}{2} = \frac{1}{72} \] - For the sequence \( D, D, A, B \): \[ P(D, D, A, B) = D \cdot D \cdot W_A \cdot W_B = \frac{1}{3} \cdot \frac{1}{3} \cdot \frac{1}{6} \cdot \frac{1}{2} = \frac{1}{108} \] - For the sequence \( D, B, D, B \): \[ P(D, B, D, B) = D \cdot W_B \cdot D \cdot W_B = \frac{1}{3} \cdot \frac{1}{2} \cdot \frac{1}{3} \cdot \frac{1}{2} = \frac{1}{36} \] 4. **Combining the Probabilities**: - The total probability \( p \) that \( B \) wins in the 4th game is: \[ p = P(A, B, D, B) + P(D, A, B, B) + P(B, D, A, B) + P(D, D, A, B) + P(D, B, D, B) \] \[ p = \frac{1}{72} + \frac{1}{72} + \frac{1}{72} + \frac{1}{108} + \frac{1}{36} \] To combine these fractions, we find a common denominator, which is \( 216 \): \[ p = \frac{3}{216} + \frac{3}{216} + \frac{3}{216} + \frac{2}{216} + \frac{6}{216} = \frac{17}{216} \] 5. **Calculating \( 6p \)**: \[ 6p = 6 \cdot \frac{17}{216} = \frac{102}{216} = \frac{17}{36} \] ### Final Answer: Thus, \( 6p = \frac{17}{36} \).

To solve the problem, we need to find the probability \( p \) that player \( B \) wins the match in the 4th game. The match is won by the first player to win 2 games. ### Step-by-step Solution: 1. **Understanding the Game Structure**: - Player \( A \) can win, draw, or lose a game with probabilities: - \( P(A \text{ wins}) = \frac{1}{6} \) - \( P(\text{Draw}) = \frac{1}{3} \) ...
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