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