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I have 6 coins
Each coin has different weight
I can weigh as many coins at a time on a scale (for example I can weigh 3 vs 2)

I want to determine which coin is second heaviest or second lightest in least possible weighings. How do I do that?

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5
  • $\begingroup$ Ask the other scale what this one would do if Monte asks it to switch curtains. $\endgroup$
    – Boba Fit
    Nov 21, 2022 at 17:43
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    $\begingroup$ Are you just making these up without finding the solution yourself? $\endgroup$ Nov 22, 2022 at 3:42
  • $\begingroup$ @ParclyTaxel I'm not really sure how it goes here. Do I post a puzzle and then an answer in the comments straight away? $\endgroup$
    – popcorn
    Nov 22, 2022 at 8:42
  • $\begingroup$ The thing is, most puzzlers in here will get tired if you post a puzzle that is very similar to a puzzle asked the previous day. Especially if you posted the previous puzzle. $\endgroup$ Nov 23, 2022 at 4:48
  • $\begingroup$ @ParclyTaxel Oh okay, thank you for the clarification then. $\endgroup$
    – popcorn
    Nov 23, 2022 at 9:17

1 Answer 1

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The same program that answered the previous question, and its proposition that only 1v1 weighings are reasonable since there is no information about the absolute weights, apply here as well.

Seven weighings are required in the worst case. Weigh three pairs $A<B,C<D,E<F$. Then sort $A<C<E$ using 3 weighings. Then the second-lightest coin is the lighter of $B$ and $C$.

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