There are 100 prisoners are in solitary cells, unable to see, speak or communicate in any way with each other. There’s a room with one light bulb, the bulb is initially off. No prisoner can see the light bulb from his own cell. Everyday, the warden picks a prisoner at random, and that prisoner goes to the that room. While there, the prisoner can toggle the bulb if he wishes. Also, the prisoner has the option of asserting the claim that all 100 prisoners have been to the living room. If this assertion is false (that is, some prisoners still haven’t been to the living room), all 100 prisoners will be shot for their stupidity. However, if it is indeed true, all prisoners are set free. Thus, the assertion should only be made if the prisoner is 100% certain of its validity.
Before the random picking begins.All the prisoners are allowed to get together to discuss a plan.
Note that each prisoner can be selected any number of times and the process will continue till the assertion is not made.

You have two hourglasses. One measured 7 minutes and the other 11 minutes.
How will you measure the 15 minutes using only these two hourglasses? Now here’s the twist you are only allowed to turn the hourglasses a total two times mean you can turn any of the glass two times or both the hourglasses one time each.

This is a classic interview puzzle asked in many interviews.
Puzzle :Given N step stair, how many number of ways can you climb if you use either 1 or 2 at a time?
For example for a stair case with 3 steps there are total 3 ways to climb it :
Way 1: 1 single step then a double step
Way 2: 1 double step and then a single step
Way 3: 3 single steps

A bad king has 1000 bottles of very expensive wine. A neighbouring King plots to kill the bad king and sends a servant to poison the wine. Unfortunately the bad king’s guards catch the servant after he has only poisoned one bottle. Alas, the guards don’t know which bottle but know that the poison is so strong that even if diluted 1,000,000 times it would still kill the king. Furthermore, it takes one month to have an effect. The bad king decides he will get some of the prisoners in his vast dungeons to drink the wine. Being a clever bad king he knows he needs to murder no more than 10 prisoners – believing he can fob off such a low death rate – and will still be able to drink the rest of the wine at his anniversary party in 5 weeks time. Explain How ?

You’re in a completely black room. Scattered on the floor are 100 coins – 90 of these are heads up and 10 of these are tails up. You are unable to distinguish which coins are heads or tails by touch or any other method you can think up like by touching etc.How do you separate the 100 coins into 2 piles, so that both piles contain the same number of face up tails?

How can you get a fair coin toss if someone hands you a coin that is weighted to come up heads more often than tails?

You are given 2 eggs.And there’s 100 floor building. Eggs can be very hard or very fragile means it may break if dropped from the first floor or may not even break if dropped from 100th floor.Both eggs are identical.You have to find the highest floor from which the egg can be dropped without breaking.What is the minimum number drops you need to make. You are allowed to break 2 eggs in the process.

There are 25 horses among which you need to find out the fastest 3 horses. You can conduct race among at most 5 horses in a single race to find out their relative speed. At no point you can find out the actual speed of the horse in a race. Find out minimum number of races are required to find the 3 horses.

The owner of a banana plantation has a camel. He wants to transport 3000 bananas to a market, which is located after the desert. The distance between his banana plantation and the market is about 1000 kilometer. So he decided to take his camel to carry the bananas. The camel can carry at the maximum of 1000 bananas at a time, and it eats one banana for every kilometer it travels.
Here’s what you have to find – What is the largest number of bananas that can be delivered to the market?