🎥 Video solution / Text Solution of this question is given below:
Check each case one by one.
Case 1: Suppose P is guilty.
P says: Q did it → False
Q says: S did it → False
R says: I did not do it → True
S says: Q lied → True
Here, two statements are false. So, P is not guilty.
Case 2: Suppose Q is guilty.
P says: Q did it → True
Q says: S did it → False
R says: I did not do it → True
S says: Q lied → True
Here, exactly one statement is false.
So, Q can be guilty.
Case 3: Suppose R is guilty.
P says: Q did it → False
Q says: S did it → False
R says: I did not do it → False
S says: Q lied → True
Here, three statements are false. So, R is not guilty.
Case 4: Suppose S is guilty.
P says: Q did it → False
Q says: S did it → True
R says: I did not do it → True
S says: Q lied → False
Here, two statements are false. So, S is not guilty.
Therefore, the guilty person is Q.