Comments on: Carnival of Mathematics #39

By: 42nd Carnival of Mathematics hosted here soon — The Endeavour

Sat, 18 Oct 2008 12:58:19 +0000

[...] few previous Carnivals of Mathematics: 41, 40, 39 ? [...]

By: Carnival of Mathematics « Carnival of Mathematics

Sun, 05 Oct 2008 22:02:02 +0000

[...] 2008/8/22: It’s the Thought that Counts (posted!) [...]

By: Jonathan

Sun, 24 Aug 2008 18:21:40 +0000

With an odd number of people we can have exactly one person in the right place for all 39 rotations (I think). For an even number, this is not possible (definitely not). But Susan beat me to it. That's two pigeonhole problems in 24 hours for me. (here too)

By: Susan B.

Sat, 23 Aug 2008 23:26:38 +0000

Great puzzle! Here’s my solution:

For each guest, consider the distance the table would have to rotate clockwise for that person to be in the correct seat. This must be a number between 0 and 38 (since rotating by 39 seats would be back where we started). But since no one is in the correct seat to begin with, each person must have a distance between 1 and 38. Since there are 38 possibilities and 39 people, at least two people are the same distance from their correct seats, and so if we rotate the table clockwise by this amount then these two will both be seated correctly. Obviously, this generalizes to any number of people.

By: A

Sat, 23 Aug 2008 21:06:37 +0000

Sure, it’d be great if someone wanted to post a solution. Once it’s up I’ll put a spoiler warning in the post so no one sees it by accident. If no one posts one for a while, I’ll put one up myself.

By: Jonathan

Sat, 23 Aug 2008 19:44:14 +0000

I like that puzzle! Thanks. Do you want solutions, or just leave it up for folks to look at?

By: Thinking about a Carnival of Mathematics « JD2718

Sat, 23 Aug 2008 19:41:06 +0000

[...] Math, Math Education, blogging, mathematics. Tags: Carnival of Mathematics trackback That’s #39 – hosted by It’s the Thought that Counts. Clever name, [...]

By: Lessons Taught; Lessons Learnt » Blog Archive » The Joy of Hex

Sat, 23 Aug 2008 17:50:38 +0000

[...] This post is featured in the 39th Carnival of Mathematics. Check it [...]

By: The Endeavour » Blog Archive » Mathematics behind the Olympic water cube

Sat, 23 Aug 2008 12:51:13 +0000

[...] found this blog via Carnival of Mathematics #39. ? [...]

By: Carnival of Mathematics #39 « 360

Fri, 22 Aug 2008 23:11:25 +0000

[...] The Carnival is here again! Celebrate the nearing end of August by visiting the 39th Carnival of Mathematics over at It’s the Thought that Counts, a blog by A and Z about “politics, society, [...]