logic
Knights and knaves
Knights always tell the truth. Knaves always lie.
Knights always tell the truth. Knaves always lie. You meet two people. One says: “We are both knaves.”
Left×Right
The speaker says “We are both knaves.”
A knight could never say that, because it would be false.
So the speaker is a knave, which means the statement is a lie, so they are not both knaves.
The other person must be a knight.
The hardest logic puzzle adds a third person who answers at random. The words da and ja give no telling which is yes.