## 82. Another Trial

- As I remember, someone once told me about a similar trial, - the White Knight continued. - There were three defendants. Each accused one of the other two, and the first defendant was telling the truth. Unfortunately, the Bar-ma-plot did not tell me whether the second defendant was lying or telling the truth, but he did inform me whether the third defendant was lying or telling the truth. This information did not allow me to determine the guilty party. Then the Bar-ma-plot told me who the third defendant accused, and I was immediately able to determine which of the three defendants was guilty. Unfortunately, I do not remember whether the third defendant was telling the truth or lying, nor do I remember who he accused.

Who is the guilty defendant this time?
82. Another trial. As in the previous problem, since A was telling the truth and accusing one of the two defendants, A must be innocent. If the White Knight learned from the Barma that C was telling the truth, then without any additional information, the White Knight would have known that B was guilty (as we saw in the solution to the previous problem). However, as is known, the White Knight could not determine without additional information who of the three defendants was guilty. Therefore, Barma must have told him that C was lying. Then the White Knight learned from Barma whom the defendant C accused, and this allowed him to determine who was guilty. If the White Knight had learned from Barma that C accused defendant A, then the White Knight would not have been able to determine who was guilty: B or C. This is why it was so important for the White Knight to hear from Barma that C accused defendant B: this meant that B must be innocent (since C was lying), and since A is also innocent, then C must be guilty.