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The Magnetized Coin


Best Answer plainglazed, 09 February 2014 - 03:36 AM

Spoiler for three weighings...

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13 replies to this topic

#11 TimeSpaceLightForce

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Posted 09 February 2014 - 09:45 AM

Spoiler for three weighings...

That is it!
You may not be able to determine the polarity but it is not asked in the OP..

Spoiler for 9coins


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#12 dgreening

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Posted 13 February 2014 - 11:27 PM

I may be missing something. some of these schemes seem to be based on knowing the weight of a regular coin.

 

I didn't read the problem that way. 

 

I believe that we only know that 11 coins weigh some unknown amount and that the 12th coin weighs slightly more or less than thatt unknown amount depending on how it is positioned..

 

Our task is to find the magnetized coin without the additional information of what a regular coin weighs.


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#13 LVan Toren

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Posted 14 February 2014 - 12:05 AM

I may be missing something. some of these schemes seem to be based on knowing the weight of a regular coin.

 

I didn't read the problem that way. 

 

I believe that we only know that 11 coins weigh some unknown amount and that the 12th coin weighs slightly more or less than thatt unknown amount depending on how it is positioned..

 

Our task is to find the magnetized coin without the additional information of what a regular coin weighs.

 

Indeed dgreening, I understand the problem the same way as you do.  If you need to know the exact weight of a regular coin, you need a supplementary weighing.  I think also about a balance with two scales, that only tells you whether what is in the left scale is heavier or lighter than what is in the right scale.


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#14 TimeSpaceLightForce

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Posted 14 February 2014 - 04:33 PM

 

I may be missing something. some of these schemes seem to be based on knowing the weight of a regular coin.

 

I didn't read the problem that way. 

 

I believe that we only know that 11 coins weigh some unknown amount and that the 12th coin weighs slightly more or less than thatt unknown amount depending on how it is positioned..

 

Our task is to find the magnetized coin without the additional information of what a regular coin weighs.

 

Indeed dgreening, I understand the problem the same way as you do.  If you need to know the exact weight of a regular coin, you need a supplementary weighing.  I think also about a balance with two scales, that only tells you whether what is in the left scale is heavier or lighter than what is in the right scale.

 

my sincere apologies..i tried to edit the info about the 1unit weight when i realized its too late..The puzzle was originally for the balance scale..but the solution for the classic odd out of 12 in 3 is applicable so i shifted to such weighing scale..With unknown unit of each, the puzzle would look like a simple problem as presented by phil..thanks all for your interest


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