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Penny's triple play


Best Answer CaptainEd, 15 February 2013 - 04:56 PM

Spoiler for with all pennies flat on the table

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11 replies to this topic

#1 bonanova

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Posted 15 February 2013 - 07:12 AM

I put a handful of pennies on the table and I wondered whether I could group them so that each penny touched three and only three of the others. It took a while but I found it was possible. I then wondered whether I could do it with fewer pennies. It was clear that I could not.

 

How many pennies were in the group?


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The greatest challenge to any thinker is stating the problem in a way that will allow a solution.
- Bertrand Russell

#2 witzar

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Posted 15 February 2013 - 02:50 PM

Is it required for each coin to touch fully table surface with one of its faces?


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#3 CaptainEd

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Posted 15 February 2013 - 04:56 PM   Best Answer

Spoiler for with all pennies flat on the table


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#4 Prime

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Posted 15 February 2013 - 05:02 PM

Spoiler for the fewest


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Past prime, actually.


#5 CaptainEd

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Posted 15 February 2013 - 05:14 PM

good solve, prime!


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#6 witzar

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Posted 15 February 2013 - 05:22 PM

Can you prove, that required arrangement is not possible with odd number of coins?


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#7 bonanova

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Posted 15 February 2013 - 07:57 PM

Spoiler for Sure

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The greatest challenge to any thinker is stating the problem in a way that will allow a solution.
- Bertrand Russell

#8 bonanova

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Posted 15 February 2013 - 08:02 PM

Spoiler for the fewest

Outside the box; off the table.
Honorable Mention for sure. :)
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The greatest challenge to any thinker is stating the problem in a way that will allow a solution.
- Bertrand Russell

#9 Prime

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Posted 15 February 2013 - 08:41 PM

Spoiler for Sure

Completely off the topic, a technical issue. I cannot see the contents of the spoiler in the post. It appears as empty line. When I "quote" the post, the spoiler becomes visible inside the "quote".


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Past prime, actually.


#10 bonanova

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Posted 15 February 2013 - 11:28 PM

There do seem some irregularities with the site. I can see the contents.

You might send a PM to Rookie1ja with your specifics.

I would have, instead of this post, but I don't know how simultaneously to PM to two people. :wacko:


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The greatest challenge to any thinker is stating the problem in a way that will allow a solution.
- Bertrand Russell




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