Riddle: A troll is on a bridge and a man tries to cross it. The troll asks him for the password and the man says he doesn't know. The troll lets him pass. Then, another man (the twin brother of the first man ) tries to cross the bridge. When he is asked the password, he says the right password but he dies. How is this possible when both men where at all the same places and both of them knew the excact same amount and none knew more than the other or had any secrets?
Answer: The password is I don't know. When the first man said I don't know, his brother heard it because they both know the same things. The second man then said I don't know as well. The troll let him pass but he slipped on a wet patch and drowned in the river