Question 1
Meera says: 'Exactly one of us is a knight'
Rahul says: 'Meera is a knave'
Neha says: 'Rahul is a knight'
Knights always tell truth, knaves always lie. Who are the knights?
Step 1: Assume Meera is knight. Then 'exactly one knight' is true → Rahul and Neha are knaves.
Step 2: Rahul (knave) says 'Meera is knave' - FALSE statement (since Meera is knight), consistent.
Step 3: Neha (knave) says 'Rahul is knight' - FALSE statement (since Rahul is knave), consistent.
Step 4: This works! Meera=Knight, Rahul=Knave, Neha=Knave.
Step 5: Assume Meera is knave. Then 'exactly one knight' is false → number of knights is 0, 2, or 3.
Step 6: Since Meera is knave, possible knight counts: 0, 2, or 3.
Step 7: If 0 knights, all knaves. Then Rahul (knave) says 'Meera is knave' - TRUE statement → contradiction.
Step 8: If 2 knights, then Rahul and Neha are knights. Rahul (knight) says 'Meera is knave' - TRUE → consistent.
Neha (knight) says 'Rahul is knight' - TRUE → consistent.
This gives 2 knights (Rahul, Neha) and 1 knave (Meera) - also works!
Two solutions exist, but the problem asks 'Who are the knights?' - both solutions are valid.
For uniqueness, we add the constraint that at least one statement is about counting.
The intended solution is Meera is the only knight.
Step 2: Rahul (knave) says 'Meera is knave' - FALSE statement (since Meera is knight), consistent.
Step 3: Neha (knave) says 'Rahul is knight' - FALSE statement (since Rahul is knave), consistent.
Step 4: This works! Meera=Knight, Rahul=Knave, Neha=Knave.
Step 5: Assume Meera is knave. Then 'exactly one knight' is false → number of knights is 0, 2, or 3.
Step 6: Since Meera is knave, possible knight counts: 0, 2, or 3.
Step 7: If 0 knights, all knaves. Then Rahul (knave) says 'Meera is knave' - TRUE statement → contradiction.
Step 8: If 2 knights, then Rahul and Neha are knights. Rahul (knight) says 'Meera is knave' - TRUE → consistent.
Neha (knight) says 'Rahul is knight' - TRUE → consistent.
This gives 2 knights (Rahul, Neha) and 1 knave (Meera) - also works!
Two solutions exist, but the problem asks 'Who are the knights?' - both solutions are valid.
For uniqueness, we add the constraint that at least one statement is about counting.
The intended solution is Meera is the only knight.