Aug 022017

Doctor gave you two types of medicine tablets (pils) A and B, and asked you to take one from each daily. The two tablets are in different bottles and look exactly same

One day, while taking the pills, you open Bottle-A and tap one pill out in your hand. Then you open the second bottle to take one pill from it, but accidentally two pills pop out from the bottle on your hand. Now you have 1 A-Pill and 2 B-Pills in your hand and you cannot distinguish them.

The pills are very expensive and you do not want to throw them, neither can you afford to take wrong pills. What should you do?
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May 122016

You are blindfolded and 10 coins are place in front of you on table. 5 are having their heads-side up and 5 are having their tails-side facing upward.

You cannot tell which way they are by touching the coin.

You are allowed to touch the coins and flip them as many times as you want.

How do you make two piles of coins each with the same number of heads-up and tails-up?
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Sep 282015

There are 10 prisoners are in 10 different cells of a prison. There is no way in which they can communicate with each other.

Each night, the warden picks one of the 10 prisoners and that prisoner is supposed to spend the entire night in the central living room. There is one bulb in the living room which can be switched on or off.

Warden puts a condition, “If any of the prisoner can tell with certainty, that all the other prisoners have spent night in the central living room, then he will free all of them. But, If the prisoner says that all the other have spent night in the living room, but that is not true, then all the prisoners will be killed”. Thus, the assertion should only be made if the prisoner is 100% certain of its validity.

Before the random picking begins, the prisoners are allowed to get together and make some strategy. But, once the strategy is made, then a prisoner cannot communicate with any other prisoner.

What plan should they agree on, so that eventually, someone will make a correct assertion?
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Sep 242015

Four glasses are placed on the four corners of a square rotating table. Each glass is either upright (up) or upside-down (down). You have to turn all the glasses in same direction (either all up or all down). There are following conditions

  1. You are blindfolded,
  2. At one time you can only change two glasses (and you cannot touch other two glasses).
  3. The table spins after each time you change the glasses.

When all the glasses comes in one direction, then a bell rings and the game stops?
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Sep 242015

You are standing before two closed doors. One of the doors leads to heaven and the other one leads to hell.

Two watchmen are standing, one in front of each door. You know one of them always tells the truth and the other always lies, but you don’t know which watchman tells the truth and who is the liar.

You can ask only one question to one of them, in order to find the way to heaven. What will you ask?
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Jul 012015

You have some work to be done by a worker in 7 days. The worker need to be paid every day after his work. The total cost of the work of 7 days is one gold bar (so every day the worker must be paid 1/7’th of the bar).

You have only one gold bar, and you can make only two cuts in that bar. How will you ensure that the worker is paid every day? Continue reading »

Jun 212015

There are 5 pirates, A, B, C, D and E. They have a strict hierarchy, A is senior to B, B is senior to C, C is senior to D and D is senior to E. So it is like (A > B > C > D > E).

These pirates have 1000 gold coins which they want to distribute among themselves. The rules of distribution is as follows:

- The most senior pirate should propose a distribution.
- All the pirates (including the most senior) will vote on whether they accept the distribution or not.
- If half or more pirates vote in the favour of distribution, then distribution is accepted and game ends.
- If more than half votes against the distribution, then the senior most pirate will be killed and the next senior most will propose a new distribution and this will continue.

When a pirate vote, they make their decision based on three factors (in this order):

  1. First of all, each pirate want to survive.
  2. Second, given survival, each pirate want to maximize the number of gold coins he gets.
  3. Third, given a situation of no-gain no-loss, each pirate would prefer to kill the other pirate.

Considering that all pirates are very strong in logic, and if a logic can be deduced, then they will deduce it. How should A distribute the coins so that he does not get killed and also gets the maximum coins possible. Continue reading »