## Search found 43 matches

- Wed Aug 01, 2007 6:32 pm UTC
- Forum: Mathematics
- Topic: Strange math thought (grid related)
- Replies:
**21** - Views:
**3534**

Yes, in theory they're the same distance. However, this is being used for a board game. We assume, then, that this would be printed and used for playing a game on a flat surface, in which case we'd be using Euclidean distances. Why would you use Euclidean distances in a board game? Ever played Risk?

- Mon Jul 23, 2007 3:47 pm UTC
- Forum: Forum Games
- Topic: Innuendo!
- Replies:
**58** - Views:
**10970**

- Tue Jun 26, 2007 10:13 pm UTC
- Forum: Mathematics
- Topic: What do you make of this guy?
- Replies:
**14** - Views:
**3750**

- Tue Jun 26, 2007 4:07 pm UTC
- Forum: Mathematics
- Topic: What do you make of this guy?
- Replies:
**14** - Views:
**3750**

- Fri Jun 22, 2007 9:52 pm UTC
- Forum: Logic Puzzles
- Topic: I dare you to solve this.
- Replies:
**82** - Views:
**36113**

http://www.drunkmenworkhere.org/129 As most people already figured out, this is generally unsolvable. I can't rigorously prove that it never has a feasible solution, but I ran a few of the matrices through an assignment problem solver, and for a given matrix, any choice will yield the exact same nu...

- Wed Jun 20, 2007 12:50 pm UTC
- Forum: Logic Puzzles
- Topic: Three gods - True, False and Random
- Replies:
**65** - Views:
**36001**

### Re: Three gods - True, False and Random

What a terrible curse, to be all-knowing but compelled to spit out random answers ... I bet the Ancient Greeks thought of this one.

- Tue Jun 19, 2007 4:21 am UTC
- Forum: Mathematics
- Topic: Medians, Altitudes, and things
- Replies:
**8** - Views:
**2737**

- Sun Jun 10, 2007 10:23 pm UTC
- Forum: Logic Puzzles
- Topic: Expected area of triangle constructed in semicircle
- Replies:
**13** - Views:
**4170**

I agree with your answer. There are three cases: both P and Q are on the semicircle; one is on the circle and one on the diameter; or both are on the diameter. Suppose both P and Q are on the semicircle. Let alpha and beta be the angles subtended along the semicircle to P and Q, respectively; assum...

- Sun May 13, 2007 1:27 pm UTC
- Forum: Mathematics
- Topic: Passionate about a calculator?
- Replies:
**139** - Views:
**24504**

Best calculator I've ever had is my Radio Shack EC-4032. My dad bought it for me for high school 13 years ago, and I've used it ever since. I had a TI-83 at one point, but it just wasn't the same. This calculator kept me sane through the tedium of high school math: it helped me learn bases other tha...

- Tue May 08, 2007 3:48 am UTC
- Forum: Mathematics
- Topic: Division Induction
- Replies:
**16** - Views:
**9198**

How about this: n^3 + 5n is divisible by 6 if and only if n^3 - n is divisible by 6. This latter polynomial is the product of three consecutive numbers: (n-1)(n)(n+1), one of which obviously must be even, and one of which must be a multiple of 3. Edit: yes, I know it's not induction. Sometimes you j...

- Tue May 08, 2007 3:45 am UTC
- Forum: Mathematics
- Topic: Multiplication of a number in a non-10 base?
- Replies:
**26** - Views:
**11628**

If you choose base n, where n-1 has many factors, then you get a lot of easy divisibility tests for free: let d be a factor of n-1; then x is a multiple of d if and only if the digits of x add up to a multiple of d. e.g. in the ever-so-convenient base 92, you can quickly see that 3TD1DZDDD7 is a mul...

- Mon May 07, 2007 11:32 pm UTC
- Forum: Logic Puzzles
- Topic: 4=5[solution]
- Replies:
**52** - Views:
**9203**

- Sat May 05, 2007 6:43 pm UTC
- Forum: Mathematics
- Topic: n and n-1
- Replies:
**6** - Views:
**4523**

### Re: n and n-1

3.14159265... wrote:edit: Also, the full factorization of n-1 would also be nice ...

It sure would be nice. That would let you factorise any number n extremely quickly: just choose a prime p bigger than n, then magically compute the full factorisations of p-1, p-2, ..., until you get to n.

- Sat May 05, 2007 6:39 pm UTC
- Forum: Mathematics
- Topic: How many digits of Pi do you know?
- Replies:
**445** - Views:
**108412**

Back in high school I had about 256 digits memorised (I had painted the first 170 or so around my room), but I'm getting old and losing my memory ... let's see ... 3.1415926535897932384626433832795028841971693993751058209749445923078164062862089986280348253421170679821480806647093844609 and now I'm ...

- Tue May 01, 2007 2:35 pm UTC
- Forum: Logic Puzzles
- Topic: Checkmate with one piece
- Replies:
**4** - Views:
**2746**

- Sun Apr 29, 2007 5:43 pm UTC
- Forum: Logic Puzzles
- Topic: Unusual Paragraph
- Replies:
**36** - Views:
**9029**

Indeed. Fynch, if you're going to be nitpicky, it helps if (a) there's a point, and (b) you quote your source in a standard and intelligible way. I must confess that I had no clue what you were talking about (I wondered if it was a new puzzle in the same vein as the one starting this thread) until R...

- Sat Apr 28, 2007 2:12 pm UTC
- Forum: Logic Puzzles
- Topic: Unusual Paragraph
- Replies:
**36** - Views:
**9029**

- Fri Apr 27, 2007 4:11 pm UTC
- Forum: Logic Puzzles
- Topic: A field of theorems
- Replies:
**12** - Views:
**3186**

I used to think about this sort of thing in graph theory classes (and I think graphs provide a much more natural and feasible structure than do fields ...). Let G be a graph with vertices (side note: Firefox spelling helper knows 'vertexes' but not 'vertices'? shame!) labelled according to graph-the...

- Mon Mar 19, 2007 3:20 pm UTC
- Forum: Logic Puzzles
- Topic: Lowest price auctions PUZZLE
- Replies:
**58** - Views:
**14931**

- Sun Mar 18, 2007 3:19 pm UTC
- Forum: Logic Puzzles
- Topic: Lowest price auctions PUZZLE
- Replies:
**58** - Views:
**14931**

skeptical scientist wrote:If there are 4 players, then 2 players playing 1, and 2 players playing 2 is a Nash equilibrium. Similarly, for 2n players, 2 players each playing 1, 2, ..., n is a Nash equilibrium.

These aren't Nash equilibria, since every player would want to switch to n+1 to become the winner.

- Sat Mar 17, 2007 6:11 am UTC
- Forum: Logic Puzzles
- Topic: Lowest price auctions PUZZLE
- Replies:
**58** - Views:
**14931**

- Fri Feb 16, 2007 6:30 pm UTC
- Forum: Forum Games
- Topic: 3 letters in a word
- Replies:
**1802** - Views:
**284996**

- Wed Feb 07, 2007 8:16 pm UTC
- Forum: Logic Puzzles
- Topic: Fornicating Chesspeople
- Replies:
**20** - Views:
**6451**

- Mon Jan 29, 2007 4:55 am UTC
- Forum: Logic Puzzles
- Topic: Riddle I Came Up With- No Maths Required!
- Replies:
**29** - Views:
**8405**

- Sat Jan 20, 2007 1:36 am UTC
- Forum: Forum Games
- Topic: 3 letters in a word
- Replies:
**1802** - Views:
**284996**

- Sat Dec 16, 2006 8:47 am UTC
- Forum: Logic Puzzles
- Topic: The Man Who Shot Liberty Valance - [solutions]
- Replies:
**15** - Views:
**5964**

If the sun is hot enough to melt a jar, then it might not matter anyway ... !

http://www.pbfcomics.com/?cid=PBF043AD-No_One_is_Thirsty.jpg#112.

http://www.pbfcomics.com/?cid=PBF043AD-No_One_is_Thirsty.jpg#112.

- Sat Dec 16, 2006 8:16 am UTC
- Forum: Logic Puzzles
- Topic: The Man Who Shot Liberty Valance - [solutions]
- Replies:
**15** - Views:
**5964**

- Sat Dec 16, 2006 2:40 am UTC
- Forum: Logic Puzzles
- Topic: The Man Who Shot Liberty Valance - [solutions]
- Replies:
**15** - Views:
**5964**

### The Man Who Shot Liberty Valance - [solutions]

solution thread to http://forums.xkcd.com/viewtopic.php?t=1021.

Nicely-worded problem. :)

I get A, B, C all possible, using the same method for each.

Edit: removed annoying white text.

Nicely-worded problem. :)

I get A, B, C all possible, using the same method for each.

Edit: removed annoying white text.

- Wed Dec 13, 2006 8:03 pm UTC
- Forum: Logic Puzzles
- Topic: Hand-Shaking
- Replies:
**8** - Views:
**4835**

- Tue Dec 12, 2006 3:39 am UTC
- Forum: Logic Puzzles
- Topic: Restrictive Basketball
- Replies:
**6** - Views:
**3094**

- Tue Dec 12, 2006 2:26 am UTC
- Forum: Logic Puzzles
- Topic: Restrictive Basketball
- Replies:
**6** - Views:
**3094**

### Re: Restrictive Basketball

You have 9 kids definitely on your team. For 9-5 players, create a plan for playing time. Try to make the schedules with that ability. Just to clarify: what do you mean by 9-5 players? (a) 9-5 = 4 (b) Kids who play daytime basketball (9:00 AM - 5:00 PM) (c) There are nine kids on the team, and 5 pl...

- Thu Dec 07, 2006 7:22 am UTC
- Forum: Logic Puzzles
- Topic: Unfair Beans [Solution]
- Replies:
**1** - Views:
**1997**

- Mon Dec 04, 2006 7:30 am UTC
- Forum: Logic Puzzles
- Topic: Temperatures
- Replies:
**60** - Views:
**13454**

By the way, you actually can multiply ordinal numbers. For example, second times third is six thth . But they aren't a distinct group from decimals. They're pretty much the same. *ahem* Please note humour in original post. Anyway, Twasbrillig, I don't know what your background is, but it sounds lik...

- Mon Dec 04, 2006 4:06 am UTC
- Forum: Logic Puzzles
- Topic: Temperatures
- Replies:
**60** - Views:
**13454**

- Mon Dec 04, 2006 2:51 am UTC
- Forum: Logic Puzzles
- Topic: Temperatures
- Replies:
**60** - Views:
**13454**

The ancient Babylonians did not have negative numbers or infinity. Therefore they did not multiply. And that's why they're not around any more. Exactly. They didn't have those, so they couldn't logically multiply, because they didn't have a numerical scale. Since temperatures are measured with sequ...

- Mon Dec 04, 2006 12:35 am UTC
- Forum: Logic Puzzles
- Topic: Unfair beans
- Replies:
**7** - Views:
**3773**

### Re: Unfair beans

I think there might be some confusion about the number of piles. There are n piles , with sizes 1, 2, 3, ..., n . For which n does Player 2 have a guaranteed win regardless of who goes first? Note that there are n piles, ranging in size from 1 to n , as opposed to a single pile with n beans. For n =...

- Mon Dec 04, 2006 12:10 am UTC
- Forum: Logic Puzzles
- Topic: Unfair beans
- Replies:
**7** - Views:
**3773**

- Sun Dec 03, 2006 10:58 pm UTC
- Forum: Logic Puzzles
- Topic: Unfair beans
- Replies:
**7** - Views:
**3773**

### Unfair beans

In keeping with the bean theme, here's something that I came up with today. As usual, two players take turns removing beans from piles; whoever takes the last bean wins. For this game, Player 1 can only remove one bean at a time, while Player 2 can only remove two beans at a time, or remove the sing...

- Sun Dec 03, 2006 6:48 pm UTC
- Forum: Logic Puzzles
- Topic: Temperatures
- Replies:
**60** - Views:
**13454**

- Sun Dec 03, 2006 3:34 am UTC
- Forum: Logic Puzzles
- Topic: More beans
- Replies:
**11** - Views:
**4173**