Stolen phone - logical deduction of culprit
Question
A mobile phone has been stolen. There are 3 suspects P, Q and R. They were questioned knowing that only one of them is guilty. Their responses are as follows: P: I did not steal. Q stole it. Q: R did not steal. I did not steal. R: I did not steal. I do not know who did it. Who stole the mobile phone?
Options
P
Q
R
Cannot be concluded
Explanation
This logic puzzle is missing the standard structural constraint (e.g., "each person makes one true and one false statement" or "only one person is telling the truth"). Without this rule, we must test for logical consistency under the sole known condition: exactly one person is guilty. If P is guilty: P's statements are (False, False). Q's are (True, True). R's are (True, True). If Q is guilty: P's are (True, True). Q's are (True, False). R's are (True, True). If R is guilty: P's are (True, False). Q's are (False, True). R's are (False, True). Because no premise dictates the distribution of truth-tellers versus liars, any of the three suspects could logically be the thief depending on who happens to be lying. Thus, the guilt cannot be mathematically isolated.
Answer: (d).
Question details
Year
2025
Paper
CSAT
Question
Q69
Section
Logical & Analytical Reasoning
Sub-topic
Logical Puzzles
Type
Inequality logic
Difficulty
Medium
Source hint
Logical deduction
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