Question 1
Deepa says: 'Amit is a liar'
Amit says: 'Priya is a liar'
Priya says: 'Deepa is a truth-teller'
Exactly one person is a liar. What can be concluded?
Let's solve step by step:
Step 1: Assume Priya is a liar.
→ Priya's statement 'Deepa is a truth-teller' is FALSE → Deepa is a liar.
→ Amit says 'Priya is a liar' - this is TRUE (since Priya is liar).
→ If Amit tells truth, then Amit is truth-teller.
→ Deepa (liar) says 'Amit is a liar' - FALSE (since Amit is truth) → consistent.
This gives: Deepa=L, Amit=T, Priya=L (two liars, one truth-teller).
Step 2: Assume Priya is a truth-teller.
→ Priya's statement 'Deepa is a truth-teller' is TRUE → Deepa is truth-teller.
→ Deepa (truth) says 'Amit is a liar' → TRUE → Amit is liar.
→ Amit (liar) says 'Priya is a liar' - FALSE (since Priya is truth) → consistent.
This gives: Deepa=T, Amit=L, Priya=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:
Priya also says: 'Exactly one of us is a liar'
With this constraint, only Step 2 works (two truth-tellers, one liar).
Therefore, Deepa and Priya are truth-tellers, Amit is a liar.
Step 1: Assume Priya is a liar.
→ Priya's statement 'Deepa is a truth-teller' is FALSE → Deepa is a liar.
→ Amit says 'Priya is a liar' - this is TRUE (since Priya is liar).
→ If Amit tells truth, then Amit is truth-teller.
→ Deepa (liar) says 'Amit is a liar' - FALSE (since Amit is truth) → consistent.
This gives: Deepa=L, Amit=T, Priya=L (two liars, one truth-teller).
Step 2: Assume Priya is a truth-teller.
→ Priya's statement 'Deepa is a truth-teller' is TRUE → Deepa is truth-teller.
→ Deepa (truth) says 'Amit is a liar' → TRUE → Amit is liar.
→ Amit (liar) says 'Priya is a liar' - FALSE (since Priya is truth) → consistent.
This gives: Deepa=T, Amit=L, Priya=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:
Priya also says: 'Exactly one of us is a liar'
With this constraint, only Step 2 works (two truth-tellers, one liar).
Therefore, Deepa and Priya are truth-tellers, Amit is a liar.