Suppose there are 4 prisoners named W, X, Y, and Z. Prisoner W is standing on one side of a wall, and prisoners X Y and Z are standing on the other side of the wall. Prisoners X, Y, and Z are all standing in a straight line facing right – so X can see prisoner Y and Z, and Y can see prisoner Z. This is what their arrangement looks like:

W(cann’t see anything) || X(can see both Y&Z) Y(can see z) Z(cann’t see anything)
Where the “||” represents a wall. The wall has no mirrors. So, prisoner W can see the wall and nothing else.

There are 2 white hats and 2 black hats. Each prisoner has a hat on his head. Each prisoner can not see the color of his own hat, and can not remove the hat from his own head. But the prisoners do know that there are 2 white hats and 2 black hats amongst themselves.

The prison guard says that if one of the prisoners can correctly guess the color of his hat then the prisoners will be set free and released.

Question :Figure out which prisoner would know the color of his own hat?

Note that the prisoners are not allowed to signal to each other, nor speak to each other to give each other hints. But, they can all hear each other if one of them tries to answer the question. Also, you can assume that every prisoner thinks logically and knows that the other prisoners think logically as well.

You have three jars that are all mislabeled. One contains peanut butter jelly
beans(Label :PB), another grape jelly jelly beans(Label : GB), and the third has a mix of both(Label :MIX) (not necessarily a 50/50 mix, could be a 1/99 mix ora 399/22 mix).

Question :How many jelly beans would you have to pull out, and out of which jars, to find out how to fix the labels on the jars?

Four people are on this side of the bridge. the bridge will be destroyed by a bomb in 17 minutes. everyone has to get across before that. Problem is that it’s dark and so you can’t cross the bridge without a flashlight, and they only have one flashlight. Plus the bridge is only big enough for two people to cross at once. The four people walk at different speeds: A fella is so fast it only takes him 1 minute to cross the bridge, B takes 2 minutes, C 5 minutes, the D it takes 10 minutes to cross the bridge. when two people cross the bridge together (sharing the flashlight),
they both walk at the slower person’s pace. can they all get across before the bridge blows up? Mentioning the speeds once again :
Person A: 1 minute
Person B: 2 minutes
Person C: 5 minutes
Person D:10 minutes

There are 8 identical coins.One of these coins is counterfeit and is known to be lighter than the genuine coins. What is the minimum number of weightings needed to identify the fake coin with a two-pan balance scale without weights?

A man has a gold chain with 7 links. he needs the service of a laborer for 7 days at a fee of one gold link per day.However, each day of work needs to be paid for separately. in other words, the worker must be paid each day after working and if the laborer is ever overpaid he will quit with the extra money. Also he will never allow himself to be owed a link.
Here’s what you have to find:
Question : What is the fewest number of cuts to the chain to facilitate this arrangement and how he will be paid?

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?