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Guest Message by DevFuse


Member Since --
Offline Last Active Feb 04 2014 08:32 PM

#337286 Betting on red

Posted by bushindo on 02 February 2014 - 12:17 AM

Interesting puzzle. I'm getting some non-intuitive results...
Spoiler for

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#336726 betting on a questionable game

Posted by bushindo on 22 November 2013 - 08:55 AM

Where is Bushindo when you need him? Mr. Bayes.


You rang?


Spoiler for

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#332156 The Best Performer

Posted by bushindo on 15 May 2013 - 12:52 AM

Anna (A), BIll (B), Cindy ©, and Dante (D) work on a project.

Together, A, B, and C can complete it in 10 days.

Together, B, C, and D can complete it in 11 days.

Together, C, D, and A can complete it in 12 days.

Together, D, A, and B can complete it in 13 days.


Who is the best performer?  Prove your answer.


Spoiler for

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#328174 Colored Duct Tapes : Hostage Terror

Posted by bushindo on 11 February 2013 - 03:13 AM

Seven International Hostages are lined up in a row .Some are standing or sitting ,
facing backward or forward.All were blindfolded with different colored duct tapes 
and ordered not to move. None has any information about the other hostages.
The terrorist leader announced to the nationals before him on the speakers that.. 
they shall all be released if they all can guess  their blindfold's color correctly 
which are  in the order as ff :  Red  Orange Yellow  Green  Blue  Violet   White 
Chi   has  2 hostages facing backward on his right, 3 sitting down on his right. 
Jap  has  2 hostages facing forward on his left, 3 standing up on his left                     
Fra   has  1 hostage facing backward on his right, 3 standing up on his left.                                           
Rus  has  3 hostages facing backward on his left, 2 sitting down on his left.                        
Eng  has  2 hostages facing forward on his right, 3 sitting down on his right.                      
Ger  has  2 hostages  facing forward on his left, 1 standing up on his right.                  
Spa  has  2 hostages facing backward on his left, 2 standing up on his left
In 60 seconds 1 hostage should raise both his  tied hands then will be pulled
behind the row and  will be shot in the head right on the spot in case he fails
to shout the correct color of his blindfold .The other  nationals  will share the 
same fate. If he is right, all the others should not fail or else everyone is going 
to die. If none of them will guess in a minute all will remain hostages..
Who would first raise his hands? 


The two possible arrangements are

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#328109 Origins of Tetris?

Posted by bushindo on 07 February 2013 - 10:49 PM

Prove that you cannot
cover a 10 x 10 chessboard with 25 figures

(Problem from Russian Math Olympiads. 6-th grade, 1964.)



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#327970 Two Fuses

Posted by bushindo on 03 February 2013 - 12:29 AM

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#327815 Staying alive with an eight-sided die

Posted by bushindo on 30 January 2013 - 06:46 PM

You glue two small square pyramids together at their bases to form an eight-sided object that becomes a fair die. You mark the opposite pairs of faces with 0 1 2 and 3.

You begin the game with $1. You roll the die; the number that shows is your new stake. That is, with equal probability you lose you dollar, you keep your dollar, you double your dollar or you triple your dollar.

A minute later, you bet each of your dollars, if any remain after the first roll, with another roll of the die; one roll for each dollar that you have, and collect your winnings, if any. After another minute passes, each of your dollars, if any, suffers the fate of another roll. To be clear, in all cases each dollar is wagered individually. As the minutes turn into years, you eventually become rich, or you go bust.

What is the probability that you go bust?

I like the conditions that Prime gave in his last game. You can simulate the game if you like. But a submitted solution must comprise an answer and a method, both of which are correct. Enjoy!



Here's an approach

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#327259 Hitting 137

Posted by bushindo on 14 January 2013 - 09:25 PM

If I repeatedly throw a fair 6-sided die, what is the probability that the running total will at one point equal 137?


With some recursive code, I get


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#327091 DOWRY

Posted by bushindo on 08 January 2013 - 08:27 PM

Okay, second time is the charm,


Spoiler for equations

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#327074 DOWRY

Posted by bushindo on 08 January 2013 - 04:43 AM

Here's an approach,

Spoiler for


Forgot about some cases in computation of winning chance. Back to the drawing board.

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#326100 I can't or I won't say

Posted by bushindo on 17 October 2012 - 05:08 PM

My take on this

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#323268 Emperor, wines, and accomplice- with a nod to meciless emperor

Posted by bushindo on 27 July 2012 - 06:22 AM

Spoiler for looks like

All correct there, except for one detail
Spoiler for detail

The emperor would also like to request more details on this drinking scheme for the sake of completeness. You see, back in college the emperor majored in Political Science, which does not require any course in Computer Science, so concrete details on how to go about doing it would be very much appreciated.
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#320600 Yes or No? I really don't know!

Posted by bushindo on 30 June 2012 - 07:37 AM

I just thought of a positive integer less than 4
said Alex to his friends Davie and Jaimie last
night at Morty's while idly tossing darts in the
back corner of the room.

It was a slow night, and Alex loved to keep things
interesting, as best he could. Now if I were to
give you two questions of the standard Yes/No
variety, I have no doubt that even you two geniuses
could deduce what my number is. So, I'll raise
the challenge a bit, and buy the next round of
beer, if you can tell me my number - with absolute
certainty - after asking me a single Yes/No question.

Davie didn't even bother to stroke his beard.
Can't be done, pure and simple. A waste of time,
If you ask me, agreed Jaimie. Neither of them
noticed the twinkle in Alex's eye as he continued
to reel them in. All right, I'll turn it around. You
pick the number and I'll ask the question. And if
you can't answer it, you'll have to say so. But it
will cost you to play. If I get it right, with certainty,
you buy. If I get it wrong, I'll buy. Either of you
up to that?

Jaimie Just walked away, muttering something
quietly about complexity. This time Davey did
stroke his beard and after a minute said, OK,
you're on.

Who bought the next round?

Here's one approach
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#320241 Which Chair you will choose ?

Posted by bushindo on 27 June 2012 - 07:44 PM

Personally I find it bizarre. I've noted that the "signal to noise ratio" (if signal means correct/true/good reasoning/answer/process, noise means bad/incorrect/false) on brainden is worse than most ad hoc forums or messages, even for the trivially easy puzzles. One of these forms is where people give answers that don't mean a thing to anyone else; the words and logic is practically gibberish in English. How does this happen? Even for most people to acknowledge a correct logical answer seems to be impossible here. If this place lacks common sense, you have to wonder what "communal" value there is given the objectives of contributing here.

In this case, the fact that we have completely different solutions means most of us are completely wrong, and yet believe we are all on the right track.
I have no problem accepting I could be wrong, but I'm the only one who has given a proof, and I have implicitly disproved all other answers. But in my experience, proofs and disproofs mean nothing to most people.

I understand your frustration of receiving no feedback after a well-reasoned and meticulous post of the solution. It is obvious from your post that you are quite smart, and I think you would fit right in this community. Personally, I generally find puzzles here to be excellent (this topic is an perfect example), and the community here includes some very fastidious, clever, and brilliant logicians. I have found myself more than once awed and humbled by the creativity and the sheer elegance of some puzzles and solutions that the Denizens come up with. I hope you will give Brainden some more time to change your opinion of its worth.

I'll have to admit that sometimes it is hard to get some feedback on this board. In this case, however, you could probably initiate some discussions about the correctness of the solution by examining other solutions (bonanova's in post #14, for instance) to see whether it is incorrect or whether you missed anything. I have examined both of your solutions, and I believe both have some errors. I may be wrong, and I often am, but I'll include those possible errors here

bonanova's solution

Spoiler for Analysis of the 70 distributions of stamps
Spoiler for 'possible error

voider's solution (the spoiler tags are added by me)

Spoiler for solution'

Spoiler for 'possible error

Having said that, I'll contribute a solution of my own. This solution will give a winning chance of 42/70 or 60%.
Spoiler for approach

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#315812 A Show Of Hands

Posted by bushindo on 14 May 2012 - 05:33 PM

Each of eight logicians has a unique positive integer less than 100 stapled to their foreheads. They stand in a circle facing one another so every logician can see everyone's number, save for their own. Each logician must discern their number and raise their hand. After all logicians have raised a hand, they must then all declare their number in unison. What strategy (within the assumed spirit of these types of puzzles) might they employ such that all are correct?


Here's an attempt.
Spoiler for Solution

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