Short Riddles and Answers


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?

Question: Your father is a scientist who has invented a red pill which, if eaten with 1 blue pill which he has invented, will grant immortality. The night he invents it, he gives you 2 red and 2 blue pills just in case one of them is lost or substandard. He also warns you that an overdose will cause the opposite effect and kill you instead. You put the pills in your pocket and leave his lab for home. On the way home, you are abducted by aliens who blindfold you and throw you into a singularity. At this point, you remember the pills your father gave you. You take them out (you can move and have enough oxygen in space for a short time), but realize that you can't tell the red pill from the blue pill. Even if you take off your blindfold, you can't see anything due to your proximity to the black hole. Given the circumstances, how do you successfully eat 1 red and 1 blue pill and survive?

Question: It is Halloween and your friends dare you to go into a haunted house. You creep up to the door, a little scared wondering what is behind the door. You go in and there is a long hallway leading out into a dark musty room with three doors. You're kind of scared once you are inside. You try to turn back, to get back outside, but when you turn around the door is closed and locked. You yell for help but there is only silence. The room is dark and you look for a light source. You see a light switch and try to turn it on. Sadly the power is out. You are terrified but have no choice but to follow the long hallway to the three doors in the pitch black. Behind one door is a bottomless pit with no end. Behind another door is an electric chair which you must sit in. Behind the last door is a pool full of acid. You must go in one of the rooms to the danger. Which one should you go through?

Question: A school's computer system was recently hacked and the school has narrowed the pool of possible hackers to 5 people that were in the computer lab: Tyler, Justin, Chandler, Paige, and Shelley. Each of them gave three statements, two of which are true and one false.

1. I didn't do it!
2. I've never hacked in my life.
3. Paige did it.
1. I didn't do it!
2. The attack was done from within the network.
3. I don't like Shelley.
1. I didn't do it!
2. I've never seen Shelley in my life.
3. Paige did it.
1. I didn't do it!
2. Shelley did it.
3. Tyler was lying when he said I did it.
1. I didn't do it!
2. Justin did it.
3. Chandler and I used to be friends.

Who hacked the system?

Poison (medium)

Question: You have been poisoned by an evil scientist. He told you that the only antidote is the saliva of a gecko. He contains saliva of six different animals. A gecko, a lizard, a koala, a tapir, a giraffe, and a cow. He hasn’t labeled he test tubes containing the saliva f the animals. On the left is a table which four of the test tubes are one. On the right is a table which two of the test tubes are on. The lizards saliva is poisonous. The lizard and gecko test tubes are on the same table. The test tubes on the left are labelled 1, 2, 3, and 4. The gecko spit will not override the lizard poison. The lizard and gecko saliva are not right beside each other. You don't know where the cow test tube is. You know that the cow saliva is in 2 or 3 however. You know that the lizard test tube is not to the right of the cow. You only have time to drink two test tubes, which side do you run toward and which test tubes do you drink?