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  Discussion about math, puzzles, games and fun.   Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ • π ƒ -¹ ² ³ °

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#1 Re: Help Me ! » 64 pawns » 2014-06-17 12:52:00

Ok but I can prove that those are not the only cofigurations.

#2 Re: Help Me ! » 64 pawns » 2014-06-17 02:44:39

No, that question on the top is the full question.

#3 Re: Help Me ! » 64 pawns » 2014-06-17 02:33:05

Well because I won't meet him for another month, and after all he is using this to puzzle me.
He won't give away the answers.

#4 Re: Help Me ! » 64 pawns » 2014-06-17 02:25:08

Again, I got it from a secondary school teacher.

#5 Re: Help Me ! » 64 pawns » 2014-06-17 02:18:42

That is terribly nonsense, because the black pawns and white pawns are identical except for the colours.
Disregarding the rule that a pawn can't attack another, we still could only have up to 64C32 ways.

#6 Re: Help Me ! » 64 pawns » 2014-06-17 01:59:20

a secondary math teacher.

#7 Re: Help Me ! » 64 pawns » 2014-06-17 01:05:52

I don't know, but since he isn't posting anything I guess he has no interest.
I think a fair estimate would be 6000 - 6500 ways. Hope the most genius-like people here will do it.

#8 Re: Help Me ! » 64 pawns » 2014-06-16 23:09:35

Why isnt Bobbym doing it?

#9 Re: Help Me ! » 64 pawns » 2014-06-16 15:03:15

Is nobody really caring about this? I really need it! Please help, people!
It is actually a nightmare to draw them up and count one by one, but I can't find any other way. I say, 99% of the people here can do it, they just have't read it.

#10 Re: Help Me ! » 64 pawns » 2014-06-16 01:35:43

So there are those 2 answers, but there are tons of other answers.
For example on a standard chessboard, if a black pawn is present on H4, there are no less than 143 solutions. And there are still other answers, when a white pawn is present on H4.
The question isn't about creating a configure, but counting them all.

#11 Help Me ! » 64 pawns » 2014-06-16 01:21:32

Replies: 31

Here is a hard problem that 99% of people here will get to answer it in 5 minutes.

"There is an 8x8 chessboard. 32 black pawns and 32 white pawns are to be placed on the board such that no pawn can capture another of the opposite color. Assume that no pawn is promoted, and the rules for the pawns to capture another piece is otherwise in power (i.e. except the promotion rule all other rules concerning the pawn is still used), find the number of ways to place the 64 pawns. (Note that we cannot turn the chessboard)

#12 Re: Help Me ! » Differential Drive... » 2013-06-27 03:13:30

I don't know a lot about physics. I'm just correcting your mistake.

#13 Re: Help Me ! » Differential Drive... » 2013-06-27 02:25:44

What do you mean by Lenovo iPad? iPad is a trademark of Apple Inc., as far as I know.
Possibly you mean a Lenovo Tablet? Tablet is the generic name.

#14 Re: Dark Discussions at Cafe Infinity » Adam and Eve » 2013-06-27 02:19:29

Not necessarily. There might have been some gene abnomalies that took shape when the bone was transformed into Eve and duplicated all X chromosomes and removed Y chromosomes. However there is an extremely low chance for this.

#15 Re: Puzzles and Games » Mobius Strip Problem » 2013-06-26 20:53:04

I have edited my post and it says odd now. Anyway, odd is enough. In Vietnam any strip with twists are called Mobius strip, whatever the number is, but internationally it's either a) 1 twist b) odd number of twist. I like the b definition more.

#16 Re: Puzzles and Games » Mobius Strip Problem » 2013-06-26 20:47:00

Well as long as there are an odd number of 180 degree turns then it's called a mobius strip. As long as it has only 1 face.

#17 Re: Introductions » Hello ^^ » 2013-06-26 20:41:54

I was in love with maths only after I was 25, when I got I stable job I start thinking of other things to do.
Anyway @bobbym I'll be away to Bulgaria and France from June 29 - July 10 without being able to bring the computer so I'm not likely to visit the forum during the mean time.

#18 Re: Puzzles and Games » Do you have what it takes to be an engineer in the Air Force? » 2013-06-25 14:12:15

What the hell is that?
And there are 3 problems:
- I don't have an Australian residence/citizenship
- I am too read-a-holic and I hates going out of a building or house
- I have respiratory problems most of the time

#19 Re: Dark Discussions at Cafe Infinity » Eurovision Microstates » 2013-06-25 02:12:19

Now I understand. The title was a ridiculous mistake. Of we were saying Eurovision Microstates then Liechtenstein has to be excluded too.

#20 Re: Dark Discussions at Cafe Infinity » Eurovision Microstates » 2013-06-25 01:36:45

The requirement for the report is neutral opinion.
What are your 3? Andorra and Liechtenstein excluded?

#21 Dark Discussions at Cafe Infinity » Eurovision Microstates » 2013-06-24 17:15:31

Replies: 5

Required knowledge:
+ What is a microstate? (a small independent state recognized by other states universally)
+ What are the ten smallest countries in Europe by land area? (Vatican. Monaco, San Marino, Liechtenstein, Malta, Andorra, Luxembourg, Cyprus, Montenegro, Slovennia)
+ What are the ten smallest countries in Europe by population? (Vatican, Monaco, San Marino, Liechtenstein, Andorra, Iceland, Malta, Luxembourg, Montengro, Cyprus)
So, in the above 2 lists, 9 of them are the same. The only difference is Slovennia/Iceland (in fact Slovennia ranks 12th in population but Iceland ranks 33th, way larger than most countries, though here we don't take territories outside Europe into account so Denmark is smaller than Iceland). But Slovennia is never considered a microstate, though Iceland does.
Vatican, Monaco, San Marino, Liechtenstein and Andorra are for now considered obvious, for their unique history has led to their independence today.
+ Vatican is the ruins of the former larger Papal States of Middle Italy
+ Monaco is a small principality independent since at least 1419, the purchase of Monaco by the House of Grimaldi
+ San Marino has been independent since 301
+ Liechtenstein, lying between Switzerland and Austro-Hungary, is the last surviving member of the Holy Roman Empire (Luxembourg was independent because at the time of German Unification it was ruled by the Dutch king)
+ Andorra has been a co-principality since 1278
The other 5 countries are not irregularities of history - Malta and Cyprus was small because it was islandic, the former Kingdom of Montenegro hold significant powers around the time of the Balkan War in the early 20th century, Luxembourg was always important in Europe since it abandoned neutral policy in 1948, and Iceland was small because of its cold climate. Also the original 5 has always been reluctant to joining organizations, the only exceptions so far have been the UN, WTO, Council of Europe and a few others (in the case of the Vatican, there is no exception at all). However Malta and Cyprus are both members of the EU, Montenegro a candidate of EU and NATO, and Iceland NATO member and EU candidate (Nordic Council is a small regional organisation and excluded), of course Luxembourg member of both.
So in my view there's only 5. What about you?

#22 Re: Puzzles and Games » Type this with your eyes closed » 2013-06-22 18:06:52

I was trying to type "I can't even pronounce it nicely..." with eyes closed.

#23 Re: Science HQ » Pluto » 2013-06-22 18:04:31

Yes. He was joking ON your post by emphasising that if #42 was true then it was far more important than #43.

#24 Re: Puzzles and Games » Type this with your eyes closed » 2013-06-22 18:01:03

I was trying to type your sentence with my eyes closed. And yet, I really can't pronounce it even in an ugly way.

#25 Re: Puzzles and Games » Type this with your eyes closed » 2013-06-22 17:57:02

I can't even pronounce it nicely...
(Note: Having me in this will make it less funny. At my IT work I always have to look at something else while typing.)

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