By signing in you confirm you are 18 or older, or have your parent’s or guardian’s consent.

UPSC Prelims 2025 CSAT, question 49

Topic: Logical reasoning

Q49

A mobile phone has been stolen. There are 3 suspects P,QP,Q and RR. They were questioned knowing that only one of them is guilty. Their responses are as follows :

P : I did not steal. QQ stole it.

Q : RR did not steal. I did not steal.

R : I did not steal. I do not know who did it.

Who stole the mobile phone ?

  1. (a) P
  2. (b) Q
  3. (c) R
  4. (d) Cannot be concludedCorrect answer

Solution.

Answer: (d) Cannot be concluded

  1. The problem states that only one of P,Q,P, Q, and RR is guilty and gives their statements, but does not specify how many suspects (or whether innocent or guilty suspects) are telling the truth.
  2. Without a rule linking guilt or innocence to truthfulness, any of the three suspects could be lying or telling the truth, so the thief cannot be concluded.