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