Question 1
Meera says: 'Divya is a liar'
Divya says: 'Rahul is a liar'
Rahul says: 'Meera is a truth-teller'
Exactly one person is a liar. What can be concluded?
Let's solve step by step:
Step 1: Assume Rahul is a liar.
→ Rahul's statement 'Meera is a truth-teller' is FALSE → Meera is a liar.
→ Divya says 'Rahul is a liar' - this is TRUE (since Rahul is liar).
→ If Divya tells truth, then Divya is truth-teller.
→ Meera (liar) says 'Divya is a liar' - FALSE (since Divya is truth) → consistent.
This gives: Meera=L, Divya=T, Rahul=L (two liars, one truth-teller).
Step 2: Assume Rahul is a truth-teller.
→ Rahul's statement 'Meera is a truth-teller' is TRUE → Meera is truth-teller.
→ Meera (truth) says 'Divya is a liar' → TRUE → Divya is liar.
→ Divya (liar) says 'Rahul is a liar' - FALSE (since Rahul is truth) → consistent.
This gives: Meera=T, Divya=L, Rahul=T (two truth-tellers, one liar).
Both assignments are valid! This puzzle has two solutions.
To guarantee a unique solution, we add a fourth person:
Rahul also says: 'Exactly one of us is a liar'
With this constraint, only Step 2 works (two truth-tellers, one liar).
Therefore, Meera and Rahul are truth-tellers, Divya is a liar.
Step 1: Assume Rahul is a liar.
→ Rahul's statement 'Meera is a truth-teller' is FALSE → Meera is a liar.
→ Divya says 'Rahul is a liar' - this is TRUE (since Rahul is liar).
→ If Divya tells truth, then Divya is truth-teller.
→ Meera (liar) says 'Divya is a liar' - FALSE (since Divya is truth) → consistent.
This gives: Meera=L, Divya=T, Rahul=L (two liars, one truth-teller).
Step 2: Assume Rahul is a truth-teller.
→ Rahul's statement 'Meera is a truth-teller' is TRUE → Meera is truth-teller.
→ Meera (truth) says 'Divya is a liar' → TRUE → Divya is liar.
→ Divya (liar) says 'Rahul is a liar' - FALSE (since Rahul is truth) → consistent.
This gives: Meera=T, Divya=L, Rahul=T (two truth-tellers, one liar).
Both assignments are valid! This puzzle has two solutions.
To guarantee a unique solution, we add a fourth person:
Rahul also says: 'Exactly one of us is a liar'
With this constraint, only Step 2 works (two truth-tellers, one liar).
Therefore, Meera and Rahul are truth-tellers, Divya is a liar.