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There are two persons A and B such that ...

There are two persons A and B such that the chances of B speaking truth of A and A speaks truth in more than 25% cases.
Statement-1: If A and B contradict each other in narrating the same statement with probability `1//2`, then it is certain that B never tells a lie.
Statement-2: The probability that A speaks truth is `1//2`.

A

Statement-1 is True, Statement-2 is True, Statement-2 is a correct explanation for Statement-1.

B

Statement-1 is True, Statement-2 is True, Statement-2 is not a correct explanation for Statement-1.

C

Statement-1 is True, Statement-2 is False.

D

Statement-1 is False, Statement-2 is True.

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To solve the problem, we will analyze the given statements and the relationships between the probabilities of A and B speaking the truth. ### Step 1: Understanding the Statements We have two statements: - **Statement 1**: If A and B contradict each other in narrating the same statement with probability 1/2, then it is certain that B never tells a lie. - **Statement 2**: The probability that A speaks the truth is 1/2. ### Step 2: Setting Up the Probabilities Let: - \( P(A) \) = Probability that A speaks the truth. - \( P(B) \) = Probability that B speaks the truth. From the problem, we know: - \( P(A) > 0.25 \) - \( P(A) = 0.5 \) (as per Statement 2). ### Step 3: Analyzing Contradictions When A and B contradict each other, it can happen in two ways: 1. A speaks the truth and B lies. 2. A lies and B speaks the truth. The probability of contradiction can be expressed as: \[ P(\text{Contradiction}) = P(A \text{ is true}) \cdot P(B \text{ is false}) + P(A \text{ is false}) \cdot P(B \text{ is true}) \] This can be mathematically represented as: \[ P(\text{Contradiction}) = P(A) \cdot (1 - P(B)) + (1 - P(A)) \cdot P(B) \] ### Step 4: Substituting Values Substituting \( P(A) = 0.5 \): \[ P(\text{Contradiction}) = 0.5 \cdot (1 - P(B)) + (1 - 0.5) \cdot P(B) \] \[ = 0.5 \cdot (1 - P(B)) + 0.5 \cdot P(B) \] \[ = 0.5 \] ### Step 5: Conclusion for Statement 1 Since the contradiction probability equals 1/2, we need to check if this implies that \( P(B) = 1 \) (i.e., B never tells a lie). If \( P(B) = 1 \): - Then \( P(B \text{ is false}) = 0 \). - The contradiction would only occur when A lies, which is \( 0.5 \cdot 0 + 0.5 \cdot 1 = 0.5 \), confirming that B never lies. Thus, **Statement 1 is true**. ### Step 6: Conclusion for Statement 2 Since \( P(A) = 0.5 \) is consistent with the condition that \( P(A) > 0.25 \), **Statement 2 is also true**. ### Final Conclusion Both statements are true, and Statement 2 correctly explains Statement 1.

To solve the problem, we will analyze the given statements and the relationships between the probabilities of A and B speaking the truth. ### Step 1: Understanding the Statements We have two statements: - **Statement 1**: If A and B contradict each other in narrating the same statement with probability 1/2, then it is certain that B never tells a lie. - **Statement 2**: The probability that A speaks the truth is 1/2. ### Step 2: Setting Up the Probabilities ...
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