Prisoners got freed

100 prisoners are stuck in the prison in solitary cells. The warden of the prison got bored one day and offered them a challenge. He will put one prisoner per day, selected at random (a prisoner can be selected more than once), into a special room with a light bulb and a switch which controls the bulb. No other prisoners can see or control the light bulb. The prisoner in the special room can either turn on the bulb, turn off the bulb or do nothing. On any day, the prisoners can stop this process and say "Every prisoner has been in the special room at least once". If that happens to be true, all the prisoners will be set free. If it is false, then all the prisoners will be executed. The prisoners are given some time to discuss and figure out a solution. How do they ensure they all go free?




Similar Riddles

Can you count the number of lines in the below picture?

Count The Number Of Lines

Asked by Neha on 27 Dec 2023


There are are five things wrong with this sentence; only geniuses will be able to to spot all of the mitstakes

Find the Mistakes

Asked by Neha on 12 Aug 2021

Can you solve the below algebraic mathematical equation?

(J+O+I+N+T)3 = JOINT

Asked by Neha on 29 May 2021


A rain drop fell from one leaf to another leaf and lost 1/4th of its volume. It then fell to another leaf and lost 1/5th of the volume. It again fell on another leaf and lost 1/5th of the volume.



This process kept repeating till it fell on the last leaf losing 1/75th of its volume.



Can you calculate the total percentage of loss from the initial volume when the drop has fallen to the last leaf accurate up to two decimal places?

Asked by Neha on 16 Feb 2021

In this image, you can see three almost identical Doraemon images. Can you spot the odd one out from them?

Odd one out Doraemon picture riddle

Asked by Neha on 19 Apr 2021

If it took eight men ten hours to build a wall, how long would it take four men to build it?

Asked by Neha on 08 May 2023


I look at you, you look at me I raise my right, you raise your left. What am I?

Asked by Neha on 24 Apr 2023

It is Secret Agent Bond Girl Friend's birthday but he is on a secret mission

Mr Bond has a secret device by which he can only use the below words for sending the message.

Dumbo, Nazi, Carrot, Ronda, Zambia, Racing, TinTin, Seou, Zareeba, Laltain, Saphire, Tar, Orphan, Audition, Biscotti.

Mr Bond sends the following message to her girlfriend:
Carrot Dumbo Nazi Racing Ronda Zambia TinTin Seou Laltain Zareeba Tar Biscotti Orphan Audition Snake

What does Mr. Bond's Message say?

Asked by Neha on 12 Apr 2026

There is a square piece of paper with a hole that is denoted by the circle on the top right side in the given picture. You have to cut the paper in a manner that it forms two and only two separate pieces of paper and then rearrange the pieces in a manner that the holes come in the centre of the paper.

Rearrange Paper

Asked by Neha on 18 Aug 2023


Four people need to cross a rickety bridge at night. Unfortunately, they have only one torch and the bridge is too dangerous to cross without one. The bridge is only strong enough to support two people at a time. Not all people take the same time to cross the bridge. Times for each person: 1 min, 2 mins, 7 mins and 10 mins. What is the shortest time needed for all four of them to cross the bridge?

River Crossing with one Torch

Asked by Neha on 31 Jul 2024

Hot Articles

Amazing Facts

Jigsaw puzzles

Jigsaw puzzles soared in popularity during the great depression, as they provided a cheap, long-lasting, recyclable form of entertainment.