Consider that three leading ladies on this blog (Saumya, Meera and Survivor) all love Hair Pins. They land up at a fair and there is a contest going on. The rules of the game are as follows. On the table there are five hair pins (Three Red and Two White). The three ladies have this piece of information. Each is taken to a separate enclosure and a pin is placed on their head (note that the participant does not know which pin is assigned to them, the only information is that there are five pins, three white and two red and one was assigned). Now the three of them are placed in a line where Saumya can observe the pins on Meera and Survivor and Meera can only observe the pin on Survivor. Given this information the question is as follows. When approached first, Saumya cannot say for sure if she has a red or a white. This information is passed on to Meera but Meera also fails to answer the question. This information is passed on to Survivor and surprise surprise surprise...Survivor nails it!
Question: How could Survivor answer the question as to what color pin was assigned to her?
Tuesday, March 04, 2008
Hair Pin Twist
Posted by Mad Max at 8:16 PM
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5 comments:
Some questions/clarifications first:
>> the only information is that there are five pins, >>three white and two red and one was assigned).
What you mean is that each knows there are 2w,2r and one of that is assigned to them. and 2 more are assigned to other two?
>>When approached first, Saumya cannot say for sure
>>if she has a red or a white. This information is >>passed on to Meera
what information is passed to Meera?
@ Mano: Only one pin is assigned to each person...and the information that is passed on is that Saumya could not figure out the color of the pin she was assigned
If saumya cannot answer, then, it should mean that survivor and meera dont both have white. If meera knows saumya's uncertainty, and if meera is not able to identify her color, then survivor cannot have white. So, survivor knows that she has "Red".
Following are the combinations
Saumya Meera Survivor
Correct White White
?? ??(W) Red
?? Red White
?? ??(R) Red
survivor helped solve the problem since she nailed the answer correct already...:)
@ Mindframes and Survivor: great job folks...cool answer...let me try to cook up more such thingyssss...
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