Search found 25 matches

by Ralp
Mon Jul 11, 2016 7:33 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 1705: "Pokémon Go"
Replies: 57
Views: 14433

Re: 1705: "Pokémon Go"

teelo wrote:Alt-text: Still waiting for the Pokémon Go update that lets you capture strangers' pets.

Mister xkcd: that update is already available in World of Warcraft. See this.

Actually it's the Dogspotting app, currently in closed beta. https://www.facebook.com/DogspottingApp/
by Ralp
Wed Aug 19, 2015 7:47 pm UTC
Forum: Logic Puzzles
Topic: Rethinking Blue Eyes - A Logic Puzzle
Replies: 97
Views: 15245

Re: Rethinking Blue Eyes - A Logic Puzzle

stekp wrote:the Guru's initial announcement that "I can see someone who has blue eyes"
provides *no new information*
Who agrees?


Probably lots of people, all of whom are wrong and haven't read this thread.
by Ralp
Thu Jul 23, 2015 9:26 pm UTC
Forum: Logic Puzzles
Topic: July 3rd, 2015 New York Times Puzzle
Replies: 14
Views: 5953

Re: July 3rd, 2015 New York Times Puzzle

What I find most interesting is the way that the free-form responses are parsed to guess whether your answer is right or wrong: var probablyWrong = ["doubl", "expon", "multipl", "^", "**", "power", "two", "2", "twic...
by Ralp
Thu May 07, 2015 3:26 pm UTC
Forum: Logic Puzzles
Topic: Another six-statements logic puzzle
Replies: 11
Views: 3332

Re: Another six-statements logic puzzle

E is true. The rest cannot be determined. Given this property, I think this puzzle fleshes out extremely well for a practical encounter in a roleplaying game, and I intend to steal it to that end. :twisted: An adventuring party exploring a crypt comes across a chamber with six talking skulls. Every...
by Ralp
Mon Nov 10, 2014 3:20 pm UTC
Forum: Logic Puzzles
Topic: Puzzle : gambling game
Replies: 4
Views: 2615

Re: Puzzle : gambling game

Unless I'm misreading something this is essentially just a Martingale strategy distributed among multiple people. The answer is infinitely many; there's no way to combine a finite number of negative expectations to add up to a positive result.
by Ralp
Fri Oct 24, 2014 8:49 pm UTC
Forum: Logic Puzzles
Topic: My write-up of the "Blue Eyes" solution (SPOILER A
Replies: 1368
Views: 421271

Re: My write-up of the "Blue Eyes" solution (SPOILER A

I think every night that passes gives them just as much new information as the guru's initial statement. I don't know if that's easily quantifiable, but you're right, in the original we have: Guru speaks: "At least one blue-eyed person" becomes common knowledge. Next day: "At least t...
by Ralp
Fri Oct 24, 2014 2:36 pm UTC
Forum: Logic Puzzles
Topic: My write-up of the "Blue Eyes" solution (SPOILER A
Replies: 1368
Views: 421271

Re: My write-up of the "Blue Eyes" solution (SPOILER A

The guru's statement is more informative in that case, but in the original problem, most of the villagers' information comes from observing every night whether anyone has left or not (or rather, knowing that everyone now knows that everyone knows [...] that everyone has observed whether anyone has l...
by Ralp
Mon Aug 25, 2014 10:09 pm UTC
Forum: Logic Puzzles
Topic: 11 letter puzzle
Replies: 3
Views: 2653

Re: 11 letter puzzle

As a very wild guess: the pairs of letters might be the initials of the cities or nations or mascots of the sports teams that competed against each other in the championships for a certain span of 6 years.
:?:
by Ralp
Mon Oct 22, 2012 10:55 pm UTC
Forum: Logic Puzzles
Topic: Ordering of five or more players
Replies: 5
Views: 1961

Re: Ordering of five or more players

Thanks all. I chose to just add a couple more rounds to the game, and change the constraints a little, such that everyone goes first, second, third etc at least once, instead of at most. It was easy to find solutions to this modified problem just by trial and error.
by Ralp
Wed Oct 17, 2012 9:14 pm UTC
Forum: Logic Puzzles
Topic: Ordering of five or more players
Replies: 5
Views: 1961

Ordering of five or more players

Is there a way to arrange a sequence of five (or n ) players taking a sequence of 20 turns, in 4 rounds of 5 (or n-1 rounds of n turns), such that: Each player gets exactly one turn each round, Each player plays first, second, third, etc during a round no more once during the game, Each player immed...
by Ralp
Thu Feb 24, 2011 3:33 am UTC
Forum: Logic Puzzles
Topic: Not friends on the earth
Replies: 19
Views: 4149

Re: Not friends on the earth

As I read it We’re just being asked for the arc length (ie. angle times radius) between vertices of a maximal (line/equilateral triangle/tetrahedron) inscribed in a sphere of known radius, along the surface of the sphere. These are of course well-known values. So the problem general...
by Ralp
Tue Feb 08, 2011 7:38 am UTC
Forum: Logic Puzzles
Topic: Infinite Balls and Jugs [solution]
Replies: 611
Views: 120450

Re: Infinite Balls and Jugs [solution]

Nope. Though infinite, the sum of 5+2.5+1.25+... is a geometric series that converges to 10. But, crucially, never equals 10. The moment you round to 10, you have a finite series, and thus it is possible to know how many balls are in the bag. I think you have it backwards; what you are saying sound...
by Ralp
Mon Feb 07, 2011 9:15 pm UTC
Forum: Logic Puzzles
Topic: Infinite Balls and Jugs [solution]
Replies: 611
Views: 120450

Re: Infinite Balls and Jugs [solution]

Surely the problem with the question is that they're imposing a finite time limit at the end of an infinite amount of time? The trick is that they've given 10 minutes, but have indicated that the addition/removal of the balls does not take an amount of time. As you iterate through the ball operatio...
by Ralp
Wed May 19, 2010 11:49 pm UTC
Forum: Logic Puzzles
Topic: Given that you have a brother...
Replies: 41
Views: 7750

Re: Given that you have a brother...

Contrast: " Given that your parents have a son, is it more likely that you're male or female? " Unless I'm mistaken this is the slightly different question that has involves a probabilty of 2/3 for reasons some people are posting. Given that you have one sibling anyway. I could have wo...
by Ralp
Thu Jan 21, 2010 11:39 pm UTC
Forum: Logic Puzzles
Topic: A simple number sequence I made
Replies: 5
Views: 1433

Re: A simple number sequence I made

Spoiler:
It's a fairly well-known sequence with some interesting properties: http://en.wikipedia.org/wiki/Look-and-say_sequence
by Ralp
Tue Aug 25, 2009 4:35 pm UTC
Forum: Logic Puzzles
Topic: Drunken sailor
Replies: 10
Views: 3197

Re: Drunken sailor

Why does a proof like this work in one or two dimensions, but fail in three, as skeptical scientist says?
by Ralp
Wed Aug 05, 2009 2:01 am UTC
Forum: Logic Puzzles
Topic: Matchup
Replies: 5
Views: 1177

Re: Matchup

Aye. Quite right, i stared At the digits for ages before looking up the answer, how long did t take you? probably less than a minute actually; it must have been back in grade school when I ran into a puzzle that had to do with the shape of letters (which letters had symmetry, or something like ...
by Ralp
Tue Aug 04, 2009 6:42 pm UTC
Forum: Logic Puzzles
Topic: Matchup
Replies: 5
Views: 1177

Re: Matchup

My answer:
Spoiler:
A. 38
B. 7
C. 16
My reasoning:
Spoiler:
It's the angularness of the numerals, right? Pointy digits, 1247 and maybe 5 are "sharp" and B only has numbers with these digits, A without, and C mixed.
by Ralp
Mon Nov 26, 2007 8:17 pm UTC
Forum: Logic Puzzles
Topic: Left/Right
Replies: 38
Views: 4300

Re: Left/Right

Strangely, I remember reading one of the only solutions to this many years ago. Some Googling of the phrase that I happen to remember, turns up the article "The Cinderella Particle" from the December 1993 issue of Discover magazine: "Even in death the muon displays odd behavior. When ...
by Ralp
Fri Nov 02, 2007 5:51 pm UTC
Forum: Logic Puzzles
Topic: Inside-out torus
Replies: 10
Views: 2565

Re: Inside-out torus

Let's say our inner-tube with a hole is colored black on the outside and white on the inside. Let's consider it to be "inside out" if we can transform it so that it's the other way around, white on the outside and black on the inside. It turns out this is possible; the result is indeed a t...
by Ralp
Wed Oct 31, 2007 6:13 am UTC
Forum: Logic Puzzles
Topic: A easy problem
Replies: 14
Views: 3194

Re: A easy problem

I don't see how the optimum strategy wouldn't just be "always cooperate". It's the optimum strategy no matter what each person knows about the other. However, there is a difference between an optimum strategy and an equilibrium strategy. Always cooperate is the former, always betray is th...
by Ralp
Tue Oct 30, 2007 9:29 pm UTC
Forum: Logic Puzzles
Topic: A easy problem
Replies: 14
Views: 3194

Re: A easy problem

No, that's the essence of the Prisoners Dilemma, that tho two aren't equivalent. Not really. If you are reasoning the same as someone, you'll pick the same answer given the same information. The essence of the Prisoner's Dilemma is that the Nash equilibrium is not the "optimal" choice. If...
by Ralp
Mon May 07, 2007 10:55 pm UTC
Forum: Logic Puzzles
Topic: Fun with maps!
Replies: 10
Views: 3306

2. What about if you fold the map up before laying it on the floor? Or crumple it into a ball? Can't we get at least two points if we fold the map with a crease sufficiently close to our location? Or will the reduced scale of the map always make any additional points "beyond the reach" of...
by Ralp
Fri May 04, 2007 11:58 pm UTC
Forum: Mathematics
Topic: n and n-1
Replies: 6
Views: 4506

Re: n and n-1

3.14159265... wrote:n-1=(2^d)(3^e)(5^f)...(P^g) with d>0

What is the value of d in terms of a,b.....,c


I don't know, but it seems like knowing this would solve the 3n-1 problem, which is notoriously unsolved. So, not to be a wet blanket, but I doubt you're going to be able to find a solution. Good luck though.
by Ralp
Sat Dec 16, 2006 9:52 am UTC
Forum: Logic Puzzles
Topic: Choose a donut
Replies: 2
Views: 3021

Choose a donut

A plate of donuts is served in the meeting room. There are three donuts left for you to choose from: two glazed donuts, and one jelly-filled. You like both glazed and jelly donuts equally. You can only take one, but later if you come back to the meeting room you hope to find at least one of the othe...

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