Knights or Knaves?

You find yourself on the Island of Knights and Knaves, a logical kingdom whose inhabitants either always lie (Knaves) or always tell the truth (Knights). You encounter three of said inhabitants, call them Alice, Bob, and Carol. You ask the following questions.

To Alice you ask, "Is Bob a Knight or a Knave?"

"A Knight," she answers.

To Bob you ask, "Are Alice and Carol both Knights or both Knaves?"

"Yes," replies Bob.

Finally, you ask Carol, "Is Bob a Knight or a Knave?"

"A Knave," she says.

Who is a Knight and who is a Knave? Click below for the answer.

Since Alice and Carol answered differently to the same question, they cannot both be Knights or Knaves, they must represent one of each type. Since this is counter to what Bob answered, he must be lying. Bob must be a Knave. That means that Carol answered truthfully, and is a Knight, and Alice did not, so she is a Knave.