Managing Director interview Puzzle

A managing director interviewed candidates for a Responsible position in his company, finally arriving at three whom he could Not separate. He called them together and said, "in my desk i have some Small sticky discs, some of which are black and some white. Close Your eyes and i will stick one on the forehead of each of you. You Must then go into the next room which has no furniture or mirrors. You will Be able to see the discs on each of the other two candidates but not your Own. Without anyone touching any of the discs and without talking To one another, the first one who can solve the problem and come out of The room and tell me what color of disc he has on his forehead, with a Logical reason, will get the job." the candidates went into the room and almost Immediately one came out and said, "i have a black disc on my forehead." he was given the job. What was his reasoning?
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Showing Answers 1 - 37 of 37 Answers

indu

  • Jul 8th, 2005
 

the person who had black disc on his head saw that on the other two heads there were white discs. since the mamager told there were both black and white discs, he guessed his must be black when the other two are white.

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siva

  • Jul 16th, 2005
 

i disgree with indu that manager has said "there were both black and white discs"..actualy mgr said there are some black & some white disks..what it wuld be is: like any two of them can see the third person's disk and also the disk reflects the image of the disk attached to the forehead of the person who is seeing the other persons disk attached to forehead and he culd know his disk color

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indu

  • Jul 20th, 2005
 

i disagree with siva b'coz there is no possibility of seeing the color of the disk as the information about the material of the disk is not provided. if the disks wud reflect the colors then the other two wud also experience the reflection. and also if the candidate knew color of his disc b'coz of reflection, there wud be no question of reasoning in the question and not a point in the manager giving them this question.

Himanshu

  • Dec 6th, 2005
 

i agree with indu.she z right

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Rajesh

  • Jul 28th, 2006
 

If a candidate sees a black and white then he can't make a logical determination of what color disk he has on his forehead.

All the candidates have to see the similar combination when seeing the other two candidates otherwise the managign director is giving unfair advantage to one candidate only. So all candidates must be seeing black on the forehead of other two candidates.

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Deepak

  • Apr 26th, 2007
 

I think the smart candidate must keep his eyes shut and not allow others to peep into his eyes. when smart candidate enters the room , he sud see into the eyes of other candidates ( glasses on face of other candidates r preferred for better reflection ) . white will be visible more in the eye pupil than the black disc. so he could easily guess what color disc is on his forehead.

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Ashish

  • May 23rd, 2007
 

Every candidate can see his forehead disc in the eyes of other candidate.

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drums4jay

  • May 31st, 2007
 

The man that came running out was a black man.  One of the two in the room had  trouble seeing the disc and strained to see it, giving away the color.

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Babu35babu

  • Mar 29th, 2010
 

Logic : A person with a black disc could see his reflection on the white discs of the other 2 .....The other could not see each other due to their reflections ...

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Venugopal668

  • Nov 27th, 2010
 

As we know black id transfer of heat stand before sunlight if it is black then it radiated a lot if it is white then it is not get radiated easily

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Hassan Farooqi

  • Jul 18th, 2011
 

The guy was very focused. He heard the words the first time and got it, we are reading it again and again and not getting it. MD said he has both black and white, and he will stick ONE of them. "i will stick one on the forehead of each of you". The focused candidate saw two black discs on the other two and knew he would be having black as well. The other other candidates who were inattentive, did not catch the words and kept guessing.

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ashwini mg

  • Jul 28th, 2011
 

because, all were closed their eyes so they cant see each others since on closing eyes . everything will be black. so he said like that

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sharan

  • Aug 28th, 2011
 

selected candidate is innluentional person,,,,, manager told him before only

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L

  • Dec 18th, 2011
 

I think its the other way around, he saw 2 black disks and realized that his was also a black disk. Since the manager was supposed to give all of them equal chances in solving the puzzle, it would be unfair for only one of them to be able to solve it and therefore they all had black disks as opposed to 2 white and 1 black

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