Question 1
Deepa says: 'Rohan took the ruby'
Rohan says: 'I did not take the ruby'
Leena says: 'Deepa is a truth-teller'
Deepa says: 'Exactly one of us took the ruby'
Who took the ruby?
Step 1: If Deepa is truth-teller, then:
- Rohan took the ruby (from statement 1).
- Exactly one person took the item (from statement 4).
- Rohan says 'I did not take it' - FALSE, so Rohan is liar (consistent).
- Leena says 'Deepa is truth-teller' - TRUE, so Leena is truth-teller.
This gives: Deepa=T, Rohan=L, Leena=T with Rohan as thief.
Step 2: If Deepa is liar, then:
- Rohan did NOT take the item (statement 1 false).
- 'Exactly one person took it' is FALSE → either 0 or 2+ people took it.
- Since Rohan didn't take it, someone else must have.
- Leena says 'Deepa is truth-teller' - FALSE, so Leena is liar.
- Rohan says 'I did not take it' - TRUE, so Rohan is truth-teller.
- This gives Deepa=L, Rohan=T, Leena=L with no thief identified - INCONSISTENT.
Therefore, the only consistent solution is Rohan took the ruby.
- Rohan took the ruby (from statement 1).
- Exactly one person took the item (from statement 4).
- Rohan says 'I did not take it' - FALSE, so Rohan is liar (consistent).
- Leena says 'Deepa is truth-teller' - TRUE, so Leena is truth-teller.
This gives: Deepa=T, Rohan=L, Leena=T with Rohan as thief.
Step 2: If Deepa is liar, then:
- Rohan did NOT take the item (statement 1 false).
- 'Exactly one person took it' is FALSE → either 0 or 2+ people took it.
- Since Rohan didn't take it, someone else must have.
- Leena says 'Deepa is truth-teller' - FALSE, so Leena is liar.
- Rohan says 'I did not take it' - TRUE, so Rohan is truth-teller.
- This gives Deepa=L, Rohan=T, Leena=L with no thief identified - INCONSISTENT.
Therefore, the only consistent solution is Rohan took the ruby.