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

Find the missing letter in the last circle logically in the given below picture.

Apply Logic in Alphabet

Asked by Neha on 02 Apr 2024


I know there are two methods by using three time the same number with a plus(+) operator , you can make sum as 60.

One of them is 20+20+20.

whats the other way ?

Asked by Neha on 28 May 2024

I have two coins.
* One of the coins is a faulty coin having a tail on both sides of it.
* The other coin is a perfect coin (heads on side and tail on other).

I blindfold myself and pick a coin and put the coin on the table. The face of the coin towards the sky is the tail.

What is the probability that another side is also tail?

Asked by Neha on 07 Jun 2023


In order to complete the racing competition, the Mexico racetrack has to submit its top and the most famous three horses to win the competition. Due to an electrical storm, all the records are cleared and no one knows which horse holds the record. They all look identical and it becomes even more difficult to differentiate the horses. There are 25 horses in the Mexico racetrack. But there can be only five horses at a time on the track. What will the least number of races that can be conducted to find out the three fastest horses?

Horse Race in Mexico

Asked by Neha on 24 Mar 2021

How many times in a given day, minutes and hour clock comes in a straight line ?

Asked by Neha on 03 Mar 2023

How many cubic feet of dirt are in a hole of one foot deep, three feet long, and two feet wide?

Asked by Neha on 13 Feb 2021


How can you leave a room with two legs and return with six legs?

Asked by Neha on 14 May 2021

Yesterday I fell from 30 feet high ladder but I don't get hurt. Why?

Asked by Neha on 11 May 2023

If a wheel has 54 spokes, how many spaces are there between the spokes?

Asked by Neha on 27 Sep 2021


who is silent in the parliament?

Asked by Neha on 29 Apr 2024

Hot Articles

Amazing Facts

Word ladder puzzle

The word ladder puzzle was invented by Lewis Carroll, author of Alice’s Adventures in Wonderland.