Search found 342 matches

by Gwydion
Wed Jan 29, 2014 10:20 pm UTC
Forum: Logic Puzzles
Topic: the poisoned wine
Replies: 27
Views: 7531

Re: the poisoned wine

SkyReaper, as stated your solution would be correct, but in the traditional wording of the puzzle, the poison has an unknown length of time before death, so you'd have to wait some length of time to make sure the taster doesn't die an hour, or a day, later. The implication (but again, not in the OP)...
by Gwydion
Sun Jan 26, 2014 4:56 pm UTC
Forum: Logic Puzzles
Topic: The philosopher, the most intelligent man and the fish
Replies: 44
Views: 12427

Re: The philosopher, the most intelligent man and the fish

All of my not-serious answers before were yes/no questions and satisfy the rest of the problem requirements. Like I said before, I believe the OP must have a more appealing answer, but I find it hard to believe that answer logically and uniquely follows from the given information - unless there is s...
by Gwydion
Wed Jan 22, 2014 5:09 am UTC
Forum: Movies and TV Shows
Topic: Robocop vs T-800
Replies: 13
Views: 4842

Re: Robocop vs T-800

I agree with Chen - the part-human Robocop would be vulnerable to things that T-800 would not. Any weapon that could hurt T-800 in the fight could also hurt Robocop, but there are things that T-800 has no need to fear (like bio and chem weapons) that could still kill/disable Robocop. Also, Robocop i...
by Gwydion
Wed Jan 22, 2014 5:01 am UTC
Forum: Logic Puzzles
Topic: The philosopher, the most intelligent man and the fish
Replies: 44
Views: 12427

Re: The philosopher, the most intelligent man and the fish

Rhombic - I hope you didn't think my comments applied to you, I was providing examples of pairs of questions which, depending on the answers, could potentially "solve" the puzzle. In other words, suggesting that I couldn't see a way to deduce from the situation a unique solution. And jokin...
by Gwydion
Tue Jan 21, 2014 3:49 am UTC
Forum: Logic Puzzles
Topic: The philosopher, the most intelligent man and the fish
Replies: 44
Views: 12427

Re: The philosopher, the most intelligent man and the fish

I see several potential ways to approach this: 1. Are you working for the CIA? 2. Are the Russians listening in on your covert meeting with the guy posing as a fishbowl? 1. Are you schizophrenic? 2. Did you take your medicine this morning? 1. Is there a bomb implanted in your brain set to go off whe...
by Gwydion
Sat Jan 11, 2014 4:11 am UTC
Forum: Mathematics
Topic: P and NP proof attempt
Replies: 15
Views: 3244

Re: P and NP proof attempt

If you want a specific criticism, mine would be that there really isn't anything being said. Your argument boils down to "Let a=1 and b=2. Also, let a=P and b=NP. a<b, therefore P<NP." It's a sneaky way of begging the question - you're stating the conclusion and arguing that the conclusion...
by Gwydion
Tue Dec 17, 2013 4:51 pm UTC
Forum: Movies and TV Shows
Topic: Blacklist
Replies: 2
Views: 2252

Re: Blacklist

I thought the raid was an interesting way to close out the half-season, but might be setting the bar for expectations a little high going into the series' future. After all, killing off semi-major characters and taking out the central location of the show forces them to take it to a much higher leve...
by Gwydion
Tue Dec 10, 2013 2:03 pm UTC
Forum: Logic Puzzles
Topic: Flipping 50 consecutive cards
Replies: 15
Views: 6100

Re: Flipping 50 consecutive cards

Adding to the last comment, n=100 also is a winning start, with the winning move to flip number 2. This forces the second player to flip 1 (only legal move) and effectively reduces the board to n=99. For me, the next step seems to be finding a losing start at all - I can conceptualize it, bu...
by Gwydion
Sat Nov 30, 2013 8:26 pm UTC
Forum: Mathematics
Topic: Chance to Win / Basic Percentages
Replies: 5
Views: 1559

Re: Chance to Win / Basic Percentages

I had a typo in my original copy-paste to Excel. My new answer submission: 0.9 1.111111111 0.8 1.25 0.7 1.428571429 0.75 1.333333333 0.8 1.25 0.4 2.5 0.45 2.222222222 0.2 5 0.95 1.052631579 0.05 20 37.14786967 Probabilities on the left. Expected boxes to open for each box on the right. Sum on the b...
by Gwydion
Sat Nov 30, 2013 2:49 pm UTC
Forum: Mathematics
Topic: Chance to Win / Basic Percentages
Replies: 5
Views: 1559

Re: Chance to Win / Basic Percentages

Snark's answer is a severe underestimate if I'm reading your questions right - the expected number of boxes to pick in order to open one is 2.5, then the odds of finding a rock would be dependent on how many you have, but are essentially 1/p as mentioned above. Therefore, the expected number of boxe...
by Gwydion
Tue Nov 12, 2013 11:09 pm UTC
Forum: Mathematics
Topic: Dogma in Math
Replies: 98
Views: 14465

Re: Dogma in Math

Alternatively: -Call the police! I've killed a man one way! *Police arrive* -So how did you kill him? -I didn't. This sounds stupid, but when you're high on Math, it's normal. Maybe the better analogy would be the following: Imagine a set of timelines in which n people are murdered. In each timelin...
by Gwydion
Wed Sep 18, 2013 5:10 am UTC
Forum: Logic Puzzles
Topic: Towers, Courtyard, and trees
Replies: 36
Views: 13752

Re: Towers, Courtyard, and trees

What actually throws me is the fact that they'd have go be assuming that there's only one solution to the puzzle and both be acting upon this one. I get the upper/lower bounds bit, and it's clever, but not being a perfect logician myself I'm not sure that I can predict them only being able to come ...
by Gwydion
Sun Jul 21, 2013 7:07 pm UTC
Forum: Logic Puzzles
Topic: 100 rooms, a real sequence, and the axiom of choice
Replies: 9
Views: 5500

Re: 100 rooms, a real sequence, and the axiom of choice

I'm not sure I consider this a riddle, or at least not a particularly elegant one. It's a really beautiful demonstration of a mathematical principle, but the solution requires each mathematician to possess knowledge of an infinite set of sequences and perfect memory for each one. And there are 100 o...
by Gwydion
Sun Jun 16, 2013 6:43 pm UTC
Forum: Logic Puzzles
Topic: Hats
Replies: 42
Views: 14904

Re: Hats

Also, I'm working on a way to split it into groups to guarantee that at least one person is correct given that less than half are rats. One (pretty elementary) result I came up with is that if you split it into groups of 2n+1, then the first n+1 people have to be able to get at least at least one p...
by Gwydion
Fri Jun 07, 2013 1:15 pm UTC
Forum: Logic Puzzles
Topic: What type of puzzle is this?
Replies: 9
Views: 5332

Re: What type of puzzle is this?

Maybe a silly question, but in sbarrack's example, why would you need the letters at all? If you add up the row sums and column sums, they should be the same total, making it a simple addition/subtraction to get the answer. Or is this just an atypical (easy) example?
by Gwydion
Tue Jun 04, 2013 11:49 pm UTC
Forum: Logic Puzzles
Topic: My write-up of the "Blue Eyes" solution (SPOILER A
Replies: 1368
Views: 418847

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

I know this is way late and nobody will probably read this but I just stumbled upon this problem today, and it took me about 20 minutes to solve it and then I just suddenly thought about how absolutely sad every single brown eyed person would be when all 100 blue eyed people got up and left. Each o...
by Gwydion
Tue Jun 04, 2013 11:45 pm UTC
Forum: Logic Puzzles
Topic: Hats
Replies: 42
Views: 14904

Re: Hats

Let's consider for a moment the rat's strategy of "Do the calculation same as the non-rats, but answer the opposite." In the case where two rats are standing in a row (but do not know that both are rats), we are guaranteed that one of them will answer correctly by this strategy. Therefore,...
by Gwydion
Wed Mar 06, 2013 5:16 pm UTC
Forum: Logic Puzzles
Topic: Birthday Problem (variation)
Replies: 11
Views: 5625

Re: Birthday Problem (variation)

About one in a billion. At least 15 means 20, 19, 18, 17, 16, or 15 sharing a birth month. The likelihood of n people out of 20 sharing a birth month is (20Cn)*11^(20-n)/12^19, where 20Cn represents the number of ways n things can be chosen from a pool of 20. The rest is simplified f...
by Gwydion
Mon Jan 21, 2013 5:27 pm UTC
Forum: Logic Puzzles
Topic: Is it fair?
Replies: 2
Views: 2789

Re: Is it fair?

Alternatively, directors serving their second consecutive term could get two votes, rather than pulling back the most recent director (who could be out of office due to being dead, for example).
by Gwydion
Mon Jan 07, 2013 3:36 pm UTC
Forum: Logic Puzzles
Topic: My write-up of the "Blue Eyes" solution (SPOILER A
Replies: 1368
Views: 418847

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

I don't think 5 is arbitrary. It's the minimum number of a population to be sure that everyone knows that everyone knows that everyone can see 1 set of a certain colour eyes. I don't mean to purport that it regresses infinitely; just to the level in that sentence (3), which I still maybe think migh...
by Gwydion
Sun Jan 06, 2013 8:40 pm UTC
Forum: Logic Puzzles
Topic: My write-up of the "Blue Eyes" solution (SPOILER A
Replies: 1368
Views: 418847

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

Deathdefy, here's a thread that might help you understand this a little better: http://forums.xkcd.com/viewtopic.php?f=3&t=80149 Specifically, note points #3, 6, and 7 which directly relate to your line of thinking. To sum up, why can you safely stop at 3 nested levels of thinking? What makes 3 ...
by Gwydion
Fri Dec 28, 2012 3:21 pm UTC
Forum: Logic Puzzles
Topic: The truthteller and the politician
Replies: 65
Views: 26060

Re: The truthteller and the politician

I haven't spent too much time thinking this through, so there may be a tricky answer I've missed. However, I believe that this is unsolvable. Since the politician is not forced to answer by any particular metric, he is able to selectively tell the truth or lie to keep you from finding out whether he...
by Gwydion
Wed Dec 26, 2012 3:39 am UTC
Forum: Logic Puzzles
Topic: A puzzle about butts
Replies: 8
Views: 6435

Re: A puzzle about butts

Unfortunately NeatNit, the third rapper does not know whether your butt is big or small. As a result, when asked what the two others would say about your butt, he does not know - either it's big and they'd both say yes, or small and they'd both say no. He'll answer randomly (as stated in the questio...
by Gwydion
Tue Dec 04, 2012 6:20 am UTC
Forum: Logic Puzzles
Topic: What isn't the answer to this puzzle?
Replies: 13
Views: 3583

Re: What isn't the answer to this puzzle?

Spoiler:
Nothing.

Assume the puzzle does not have a solution. Therefore, the answer to the puzzle can't be "nothing" because no solution exists.

Instead assume a solution exists. Therefore, the answer to the puzzle can't be nothing because it has to be something.
by Gwydion
Fri Nov 30, 2012 4:03 pm UTC
Forum: Logic Puzzles
Topic: Coins and balances - a different twist
Replies: 14
Views: 4674

Re: Coins and balances - a different twist

I don't follow. After 4 weighings, you have 5, 6 or 9 bags known to be the proper weight. With 6, weighing the unweighed bag against one of the proper weight tells you whether it's heavy or light, and hence whether the heavier or lighter of the unbalanced pair is the other bag of improper weigh...
by Gwydion
Fri Nov 30, 2012 1:36 pm UTC
Forum: Logic Puzzles
Topic: Coins and balances - a different twist
Replies: 14
Views: 4674

Re: Coins and balances - a different twist

Solid work - I went to bed last night with no replies, and woke up this morning with multiple replies and a right answer! Solving the lower bound is easy, actually finding a set of groupings that does it was (I think) much harder. And yes, jestingrabbit's solution would have been 6, in the worst-cas...
by Gwydion
Wed Nov 28, 2012 11:50 pm UTC
Forum: Logic Puzzles
Topic: Coins and balances - a different twist
Replies: 14
Views: 4674

Coins and balances - a different twist

I read through many many threads to try and make sure this hasn't been done - I think this is a different take than has been done previously, but someone stop us if it has. A group of pirates make off with 9 sacks of 1000 gold coins each, with plans to divide them up the next day. That night, one of...
by Gwydion
Mon Oct 29, 2012 4:51 am UTC
Forum: Mathematics
Topic: Statistical Significance Question
Replies: 3
Views: 942

Re: Statistical Significance Question

If all of the studies show the same thing, but some weren't statistically significant, one possible source would be the power of the studies, which reflects in part the relative size of the samples. Were the studies sufficiently powered to demonstrate a significant difference of the magnitude you're...
by Gwydion
Fri Oct 19, 2012 4:51 pm UTC
Forum: Logic Puzzles
Topic: Fair Notification
Replies: 14
Views: 4427

Re: Fair Notification

And, besides, because once someone has bought something once, they can never buy it again unless there's noone on the list who's never bought it, the problem will naturally fall away over time. You underestimate the number of poor college students who will do anything for twenty bucks. And every ye...
by Gwydion
Sat Oct 13, 2012 2:16 am UTC
Forum: Music
Topic: Perfect Moments In Music
Replies: 396
Views: 198366

Re: Perfect Moments In Music

I agree with so much of the thread to date, it's hard to single out just a couple. I will nth the guitar mutes from Radiohead's Creep as a moment that really gives me chills - the first time I heard the song, I remember thinking "Ok this is just another sad radiohead song wait what did he just ...
by Gwydion
Mon Aug 27, 2012 1:02 pm UTC
Forum: Movies and TV Shows
Topic: Dark Knight Rises
Replies: 245
Views: 39823

Re: Dark Knight Rises

Remember the second film, where he was living out of that trailer thing that's not connected to him in any way at all? He definitely had spare stuff there, including a Bat-suit. Also, he didn't lose his mansion in the stock thing, he explicitly states "They're letting me keep the house." ...
by Gwydion
Wed Aug 15, 2012 5:53 pm UTC
Forum: Movies and TV Shows
Topic: Dark Knight Rises
Replies: 245
Views: 39823

Re: Dark Knight Rises

So were Bane and Miranda both in the League of Shadows, or what? And why? I believe the explanation given in the movie was that Miranda (aka Talia) was brought into the League when she escaped and tracked down her father, Ra's. Bane was also a member of the League, but was kicked out by...
by Gwydion
Wed Aug 15, 2012 5:47 pm UTC
Forum: Logic Puzzles
Topic: My write-up of the "Blue Eyes" solution (SPOILER A
Replies: 1368
Views: 418847

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

Please tell me which step this logic fail. Adam sees three people with blue eyes Adam know that blue eyes exist Adam knows that Bart can see at least two blue eyes Adam knows that Bart knows blue eyes exist Adam knows the same for Carl, Dave, etc. Bart, Carl, Dave, etc. are in the same boat as Adam...
by Gwydion
Wed Aug 15, 2012 1:41 pm UTC
Forum: Logic Puzzles
Topic: My write-up of the "Blue Eyes" solution (SPOILER A
Replies: 1368
Views: 418847

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

My thought on working with four or more is this "logical statement" It's impossible for me to see three people with blue eyes without knowing that everyone else can see at least two people with blue eyes. And if that is true, then I know that everyone knows that blue eyes exist. If the Gu...
by Gwydion
Tue Aug 14, 2012 3:45 am UTC
Forum: Logic Puzzles
Topic: My write-up of the "Blue Eyes" solution (SPOILER A
Replies: 1368
Views: 418847

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

The Guru doesn't provide new information so much as the Guru provides a starting point; a Day-Zero. Sure, everyone knew that there were at least 99 people with blue eyes, and as many as 101. What they didn't have was a way for that information to be relevant until EVERYONE started counting days. So...
by Gwydion
Mon Aug 06, 2012 7:54 pm UTC
Forum: Movies and TV Shows
Topic: The Newsroom (HBO series)
Replies: 13
Views: 4450

Re: The Newsroom (HBO series)

So far I like this series, especially the intro, it's really neat. That being said: Wasn't 100% Happy with the treatment of the Fukushima bit (I was hoping that the 'Good News' take on that disaster would be to focus on the y'know, giant flood and fossil fuel power plants that w...
by Gwydion
Thu Aug 02, 2012 4:51 pm UTC
Forum: Gaming
Topic: KOTOR 2
Replies: 11
Views: 2759

Re: KOTOR 2

Actually, this is a known bug - if you finish Tatooine first, leave, then return to the dragon cave before completing a second world's main quest, you get stuck fighting Calo when you try to exit. Normally he's saved for after the second world, so you're essentially one main quest and several sidequ...
by Gwydion
Fri Jul 20, 2012 12:48 am UTC
Forum: Logic Puzzles
Topic: Seventeen "Blue Eyes" Objections and Responses [SPOILER]
Replies: 73
Views: 41036

Re: Seventeen "Blue Eyes" Objections and Responses [SPOILER]

From the perspective of an islander(doesn't know the own color of their eyes) does anyone have a chance of being wrong? In this specific situation, no. The islanders are, however, no longer perfect logicians and there are scenarios where many of them would be wrong. not just in this specific situat...
by Gwydion
Mon Jun 25, 2012 11:35 am UTC
Forum: Logic Puzzles
Topic: A prison with an infinite number of cells
Replies: 28
Views: 8802

Re: A prison with an infinite number of cells

Naturally, any process for reassigning rooms of an infinite number of prisoners will be tricky and lead to some unsatisfying answers in the short run, but look at it this way: Once you move prisoners from cell 1 (call this move 0), there will be an excess of prisoners in cell 2, as lorb poin...
by Gwydion
Tue Jun 19, 2012 4:16 pm UTC
Forum: Mathematics
Topic: Hi/Game structure for financial markets
Replies: 36
Views: 8164

Re: Hi/Game structure for financial markets

So, if I'm understanding you right, you're suggesting that we try to identify those factors whose effect on the outcome are the strongest, which is to say not effected through an indirect mechanism, rather than try to recognize all of the possible factors involved? I'm still not sure why that isn't ...

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