Question 1
Leena says: 'Exactly one of us is a knight'
Kiran says: 'Leena is a knave'
Harsha says: 'Kiran is a knight'
Knights always tell truth, knaves always lie. Who are the knights?
Step 1: Assume Leena is knight. Then 'exactly one knight' is true → Kiran and Harsha are knaves.
Step 2: Kiran (knave) says 'Leena is knave' - FALSE statement (since Leena is knight), consistent.
Step 3: Harsha (knave) says 'Kiran is knight' - FALSE statement (since Kiran is knave), consistent.
Step 4: This works! Leena=Knight, Kiran=Knave, Harsha=Knave.
Step 5: Assume Leena is knave. Then 'exactly one knight' is false → number of knights is 0, 2, or 3.
Step 6: Since Leena is knave, possible knight counts: 0, 2, or 3.
Step 7: If 0 knights, all knaves. Then Kiran (knave) says 'Leena is knave' - TRUE statement → contradiction.
Step 8: If 2 knights, then Kiran and Harsha are knights. Kiran (knight) says 'Leena is knave' - TRUE → consistent.
Harsha (knight) says 'Kiran is knight' - TRUE → consistent.
This gives 2 knights (Kiran, Harsha) and 1 knave (Leena) - 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 Leena is the only knight.
Step 2: Kiran (knave) says 'Leena is knave' - FALSE statement (since Leena is knight), consistent.
Step 3: Harsha (knave) says 'Kiran is knight' - FALSE statement (since Kiran is knave), consistent.
Step 4: This works! Leena=Knight, Kiran=Knave, Harsha=Knave.
Step 5: Assume Leena is knave. Then 'exactly one knight' is false → number of knights is 0, 2, or 3.
Step 6: Since Leena is knave, possible knight counts: 0, 2, or 3.
Step 7: If 0 knights, all knaves. Then Kiran (knave) says 'Leena is knave' - TRUE statement → contradiction.
Step 8: If 2 knights, then Kiran and Harsha are knights. Kiran (knight) says 'Leena is knave' - TRUE → consistent.
Harsha (knight) says 'Kiran is knight' - TRUE → consistent.
This gives 2 knights (Kiran, Harsha) and 1 knave (Leena) - 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 Leena is the only knight.