7.5. 16 travelers, each of whom is either a liar or a knight (liars always lie, knights always tell the truth), settled into 3 rooms of a hotel. When everyone gathered in their rooms, Basil, who was staying in the first room, said: "There are more liars than knights in this room right now. Although no - there are more knights than liars in this room right now." After that, Basil went to the second room and said the same two statements there. And then he went to the third room and said the same two statements there as well. How many knights could there have been among these 16 travelers?
Answer: 9 knights.

Solution: Since Vasily's statements contradict each other, Vasily is a liar. Therefore, both of Vasily's statements (about each room) are false, and in each room (when he was there) the number of liars and knights was equal. This means that in each room, without Vasily, there was one more knight than liar. Therefore, among the 15 remaining travelers, there are 3 more knights than liars, which means there are 9 knights and 6 liars among them.

Comment: Correct answer without justification - 0 points.

Showing that Vasily is a liar - 1 point.

Proving that in each room, without Vasily, there is one more knight than liar - 4 points.