What's new
USCHO Fan Forum

This is a sample guest message. Register a free account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members through your own private inbox!

  • The USCHO Fan Forum has migrated to a new plaform, xenForo. Most of the function of the forum should work in familiar ways. Please note that you can switch between light and dark modes by clicking on the gear icon in the upper right of the main menu bar. We are hoping that this new platform will prove to be faster and more reliable. Please feel free to explore its features.

Monty Hall, we have a PROBLEM

Re: Monty Hall, we have a PROBLEM

In the past few months, I came across a number puzzle called KenKen. Far more interesting than Sudoku.

KenKen is both mathematical and logical while Soduku is purely logical. The numerals in Soduku could be replaced by any nine symbols.
 
Re: Monty Hall, we have a PROBLEM

Two years ago, one of my relatives celebrated a birthday: his/her age was 3 times a prime number.
Last year, his/her age was twice a prime number.
This year, his/her age is a prime number.

How old is s/he?




I found 3 possible solutions for regular human ages, and 4 additional possible solutions for "Biblical" ages (i.e., less than 1,000)
 
Last edited:
Two years ago, one of my relatives celebrated a birthday: his/her age was 3 times a prime number.
Last year, his/her age was twice a prime number.
This year, his/her age is a prime number.

How old is s/he?




I found 3 possible solutions for regular human ages, and 4 additional possible solutions for "Biblical" ages (i.e., less than 1,000)

5 - but was s/he vaccinated?
 
Re: Monty Hall, we have a PROBLEM

A large box contains five cone-shaped hats, three of which are colored red and two blue. After having been told about the colors of all the hats, three logically gifted but blind-folded people are each asked to take one hat out of the box and put it on his or her head.

Now each in turn is allowed to take the his/her own blindfold off and make a determination as to what color hat they have on.

Subject #1 removes his blindfold, and after a moment says "I have no idea what color hat I'm wearing."
Subject #2 then removes her blindfold, and after a moment admits the same about her own hat.
Subject #3 thinks for a moment and, without having to remove her blindfold, declares the color of hat she's wearing ... and is correct.

What color hat is #3 wearing, and how did she come to the correct conclusion?
 
Last edited:
Re: Monty Hall, we have a PROBLEM

Lady in red
Is dancing with me

She's wearing a red hat, the other two were each wearing blue hats, leaving red as the only available color. The first two would have seen that the other participants were evenly split between red and blue, therefore not knowing at a 100% CI what was on top of his or her own head.
 
A large box contains five cone-shaped hats, three of which are colored red and two blue. After having been told about the colors of all the hats, three logically gifted but blind-folded people are each asked to take one hat out of the box and put it on his or her head.

Now each in turn is allowed to take the his/her own blindfold off and make a determination as to what color hat they have on.

Subject #1 removes his blindfold, and after a moment says "I have no idea what color hat I'm wearing."
Subject #2 then removes her blindfold, and after a moment admits the same about her own hat.
Subject #3 thinks for a moment and, without having to remove her blindfold, declares the color of hat she's wearing ... and is correct.

What color hat is #3 wearing, and how did she come to the correct conclusion?


3 is wearing red.
1 doesn't know, which means at least one, but possibly both, of 2 & 3 is wearing red. It also means they are not both wearing blue, because 1 would know he had red if they were.

2 then says they don't know. However, if 3 had blue then 2 would know they had red since they could not both be blue. Since 2 doesn't know, that means 3 must be red.
 
Last edited:
Lady in red
Is dancing with me

She's wearing a red hat, the other two were each wearing blue hats, leaving red as the only available color. The first two would have seen that the other participants were evenly split between red and blue, therefore not knowing at a 100% CI what was on top of his or her own head.

Right answer but wrong reasoning. 1 or 2 could each have either color.
 
Re: Monty Hall, we have a PROBLEM

Right answer but wrong reasoning. 1 or 2 could each have either color.

Correct, I wasn't taking into account the fact that 3 would've been thinking about the reasoning 1 and 2 would need to use in order to make their answers.
 
Re: Monty Hall, we have a PROBLEM

Right answer but wrong reasoning. 1 or 2 could each have either color.

<strike>Sort of</strike> Yes - there are <strike>3</strike> oopsee 4 scenarios where the story comes to the same conclusion ... all of them ending with #3 wearing red:


#1 #2 #3
RED RED RED
RED BLUE RED
BLUE BLUE RED
RED BLUE RED
 
Last edited:
Re: Monty Hall, we have a PROBLEM

#1 can look and see 3 in blue and 2 in red.
the #2 can look and see 3 in blue and 1 in red.

there are five hats. one blue and one red are still on a table.
 
Re: Monty Hall, we have a PROBLEM

:shiva six-handed face palm:

I saw an episode of Jeopardy in which all three contestants ended with $0! :eek:

The one in the lead committed the inexcusable error of betting everything. The cardinal rule if you are in the lead is that you only bet $1 more than the highest total that the second-place contestant can possibly reach if they bet everything. How can anyone "smart enough" to get on the show in the first place not do that?? :(

This rule, in turn, opens up some really interesting game theory approaches for second and third.

The game theory approaches for # 2 are quite interesting and probably are too varied to discuss, since they depend upon how much # 2 has relative to # 1, and also depend upon whether # 2 expects # 3 to use optimal game theory or not.

In other words, if # 1 has $15,000, # 2 has $10,000, then # 1 bets $5,001. Ignoring # 3 strategy for now, # 2 bets $0, since if # 1 is wrong, $10,000 > $9,999. # 1 "has to" always follow the cardinal rule, or else loses if # 2 bets everything and is right. # 1 cannot take that risk.

Generally, if I am in third, I have to hope that 1 and 2 are both wrong. And so I bet $1 more than what # 1 would end up with assuming s/he followed the rule just cited, and then was wrong.

If # 3 has $6,000, say, and # 1 bets $5,001, # 3 bets $4,000...unless # 3 anticipates # 2 to bet $0, and so bets $4,001.

It is annoying to me the number of times when it is "obvious" that the optimal bet for one of the contestants is $0 and then they don't do it.
 
Re: Monty Hall, we have a PROBLEM

Was that the second episode of the current run? That ended all with $0. It's called pulling a Claven. Named after Cliff Claven, the character from Cheers, who went on Jeopardy, got a big lead going into Final, and got cocky and bet it all.
 
Re: Monty Hall, we have a PROBLEM

:shiva six-handed face palm:

I saw an episode of Jeopardy in which all three contestants ended with $0! :eek:

The one in the lead committed the inexcusable error of betting everything. The cardinal rule if you are in the lead is that you only bet $1 more than the highest total that the second-place contestant can possibly reach if they bet everything. How can anyone "smart enough" to get on the show in the first place not do that?? :(

This rule, in turn, opens up some really interesting game theory approaches for second and third.

The game theory approaches for # 2 are quite interesting and probably are too varied to discuss, since they depend upon how much # 2 has relative to # 1, and also depend upon whether # 2 expects # 3 to use optimal game theory or not.

In other words, if # 1 has $15,000, # 2 has $10,000, then # 1 bets $5,001. Ignoring # 3 strategy for now, # 2 bets $0, since if # 1 is wrong, $10,000 > $9,999. # 1 "has to" always follow the cardinal rule, or else loses if # 2 bets everything and is right. # 1 cannot take that risk.

Generally, if I am in third, I have to hope that 1 and 2 are both wrong. And so I bet $1 more than what # 1 would end up with assuming s/he followed the rule just cited, and then was wrong.

If # 3 has $6,000, say, and # 1 bets $5,001, # 3 bets $4,000...unless # 3 anticipates # 2 to bet $0, and so bets $4,001.

It is annoying to me the number of times when it is "obvious" that the optimal bet for one of the contestants is $0 and then they don't do it.

The kind folks at J! Archive have you covered.

http://www.j-archive.com/wageringcalculator.php

Be sure to find your way to the glossary for explanations of some of the various wagering scenarios.

http://www.j-archive.com/help.php#glossary
 
Re: Monty Hall, we have a PROBLEM

Who are three people who have never been in my kitchen?
 
Back
Top