Four girls participated in a running race. After the race, each of them was asked what place they finished in. Anna said: I was neither first nor last. Bella: I was not first. Csilla: I was first. Dóra: I was the last. Someone who saw the race said: Out of the four answers, three are true, one is false. - Who told a lie? Who was the first?
Csilla told the truth, she was the first, because if O's statement were false, then the other three statements would be true, but then no one would have been first. According to this, Bella also told the truth.

Anna could not have lied either, because that would mean she came last (since she could not have been first), but then Dóra would not have told the truth. Therefore, only Dóra could have lied, and this is possible if Bella came last, and Anna and Dóra shared the 2nd and 3rd places.

János Havas (Budapest, Berzsenyi D. g. II. o. t.)

Note. We could also start the solution this way. If Anna's statement were false, then she would have either been first or last, so in addition to her, either Csilla or Dóra's statement would also be false.