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In a class of five students $\text{P, Q, R, S}$ and $\text{T},$ only one student is known to have copied in the exam. The disciplinary committee has investigated the situation and recorded the statements from the students as given below.

$\text{Statement of P: R}$ has copied in the exam.

$\text{Statement of Q: S}$ has copied in the exam.

$\text{Statement of R: P}$ did not copy in the exam. 

$\text{Statement of S:}$ Only one of us is telling the truth.

$\text{Statement of T: R}$ is telling the truth.

The investigating team had authentic information that $\text{S}$ never lies.

Based on the information given above, the person who has copied in the exam is

  1. $\text{R}$
  2. $\text{P}$
  3. $\text{Q}$
  4. $\text{T}$
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Given the statements:

  • $\text{Statement of P:  R}$ has copied in the exam.
  • $\text{Statement of Q:  S}$ has copied in the exam.
  • $\text{Statement of R:  P}$ did not copy in the exam. 
  • $\text{Statement of S: }$ Only one of us is telling the truth.
  • $\text{Statement of T:  R}$ is telling the truth.

Based on the above statements, we can make the pictorial representation.

$\qquad \begin{array}{ccccc} \underbrace{\text{P}}_{\text{R}\;\Large{\checkmark}} & \underbrace{\text{Q}}_{\text{S}\;\Large{\checkmark}} & \underbrace{\text{R}}_{\text{P}\Large{\times}} & \underbrace{\text{S}}_{\text{Only one is true}}  & \underbrace{\text{T}}_{\text{R is true}} \\\hline  \underbrace{\underbrace{\text{P}}_{\text{R}\;\Large{\checkmark}}}_{{\color{Red}{\text{False}}}} & \underbrace{\underbrace{\text{Q}}_{\text{S}\;\Large{\checkmark}}}_{{\color{Red}{\text{False}}}} & \underbrace{\underbrace{\text{R}}_{\text{P}\Large{\times}}}_{{\color{Red}{\text{False}}}} &\underbrace{\underbrace{\text{S}}_{\text{Only one is true}}}_{{\color{Green}{\text{Always True}}}}  & \underbrace{\underbrace{\text{T}}_{\text{R is true}}}_{{\color{Lime}{\text{True}}}} \\\hline  \underbrace{\text{P}}_{\text{R}\;\Large{\times}} & \underbrace{\text{Q}}_{\text{S}\;\Large{\times}} & \underbrace{\text{R}}_{\text{P}\;\Large{\checkmark}}  & & \end{array}$

$\therefore$ The person who has copied in the exam is ${\color{Blue}{\text{P}.}}$

Correct Answer $:\text{B}$

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The correct answer based on the provided information is (B) P.

Here's how we can reason:

  1. S always tells the truth: This key information establishes a starting point for analysis.

  2. S's statement: "Only one of us is telling the truth" can only be true if the other statements by students are all lies.

  3. Analyzing contradictions: If all other statements were lies, then T's statement claiming R's truthfulness would also be false, contradicting the authentic information that S never lies.

  4. Identifying the truth: Therefore, at least one statement besides S's must be true. Since S's statement implies all others are lies, the true statement must be one that implies at least one other statement as true.

  5. Evaluating statements:

    • R's statement claiming P didn't copy cannot be true because it would contradict S's implication of everyone else lying.
    • Q's statement about S is already established as false because of S's truthfulness.
    • This leaves P's statement accusing R as the most likely candidate for truth.
  6. Conclusion: If P's statement claiming R copied is true, then S's implication of one truth is fulfilled, and all other statements become lies, consistent with the initial analysis.

Therefore, based on the available information and analyzing the logical implications of S's truthfulness, the most likely person who copied in the exam is P.

Answer: