Petr, Mojmír, Karel, and Eva advanced to the district round. At school, they then stated:

Eva: "I was neither first nor last among our four."

Mojmír: "I was not the last among our four."

Karel: "I was the first among us."

Petr: "I was the last among our four."

Three of them were telling the truth, one was lying. Who was the best among them in the district round? (M. Volfová)
If lhali:

> Eva: So in fact, she would be the first or the last. However, this contradicts the statements of Karel and Petr.

D Mojmír: He would be the last, but that would mean Petr is also lying.

> Petr: In reality, he would not be the last, but it wouldn't be Eva, Mojmír, or Karel either, so no one could be the last.

Therefore, neither Eva, Mojmír, nor Petr could have lied. Karel lied, and the others spoke the truth. Mojmír was the first.

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