23 Prisoners and 2 Switches

Question: A prison has 23 prisoners in 23 different cells. The prisoners have no way to communicate with each other in any way from their cells. There is another room, the rec room, that has two switches on the wall (A and B). The switches have on and off positions but they start in an unknown position.

Prisoners are randomly taken to and from the rec room one at a time. They must change the position of only one of the two switches each time they go to the room. At any point a prisoner can yell out, "Every prisoner has been here!" If the prisoner is correct that all of the prisoners have visited the rec room, then they all go free. If they aren't correct then they are all executed.

Before they start they are given one planning session during which they can discuss a method to win the game. What method can they use to ensure they all go free?

Riddle Discussion

Similar Riddles

Question: "The Captain is my brother," testified the soldier. But the Captain testified he didn't have a brother. Who is telling the truth?

Always There (medium)

Question: What goes through towns and over hills, but never moves?

Question: What tastes better than it smells?

Question: In a house of Kardak's family each brother have a sisters as double as their brothers and each sister have brothers as same as their sister. How many brothers and sisters in Kardak's family ?

Question: What goes in the water black and comes out red?