CTK Exchange
Front Page
Movie shortcuts
Personal info
Awards
Reciprocal links
Terms of use
Privacy Policy

Interactive Activities

Cut The Knot!
MSET99 Talk
Games & Puzzles
Arithmetic/Algebra
Geometry
Probability
Eye Opener
Analog Gadgets
Inventor's Paradox
Did you know?...
Proofs
Math as Language
Things Impossible
My Logo
Math Poll
Other Math sit's
Guest book
News sit's

Recommend this site

Manifesto: what CTK is about Search CTK Buying a book is a commitment to learning Table of content |Store| Things you can find on CTK Chronology of updates Email to Cut The Knot Recommend this page

CTK Exchange

Subject: "Fun probability question"     Previous Topic | Next Topic
Printer-friendly copy     Email this topic to a friend    
Conferences The CTK Exchange High school Topic #335
Reading Topic #335
Owen
Member since Nov-11-05
Nov-17-05, 07:20 AM (EST)
Click to EMail Owen Click to send private message to Owen Click to view user profileClick to add this user to your buddy list  
"Fun probability question"
 
   Here is a fun problem for those of you haven't seen it. I believe it may be found in the Dover book entitled something along the lines of "50 Probability Problems" (a great little book).

You, Annie, and Bob will be participating in a truel (a duel with 3 people). The three of you will take turns firing one shot from your gun; once a person is hit he/she is out of the competition. You have the advantage of going first, but you only hit your intended target 30% of the time. Annie goes next, and she never misses. Bob shoots third, and he hits his intended target 50% of the time. What should your strategy be as the first shooter? (Assume a rotation of You, Annie, Bob, You, Annie, Bob, etc. until one person is hit, afterwhich the two remaining competitors take turns shooting.)


  Alert | IP Printer-friendly page | Reply | Reply With Quote | Top

  Subject     Author     Message Date     ID  
  RE: Fun probability question mpdlc Nov-17-05 1
     RE: Fun probability question Owen Nov-17-05 2
         RE: Fun probability question alexbadmin Nov-19-05 4
             RE: Fun probability question mr_homm Nov-22-05 5
                 RE: Fun probability question alexbadmin Nov-22-05 6
  RE: Fun probability question alexbadmin Nov-18-05 3

Conferences | Forums | Topics | Previous Topic | Next Topic
mpdlc
guest
Nov-17-05, 12:09 PM (EST)
 
1. "RE: Fun probability question"
In response to message #0
 
   Hi Owen,

Sometime ago I bought that book you have referred, someone borrowed from me and I lost it as happen frequently with lended books. I believe its author is someone call Frederick Hosteller or alike, and I do remember more or less the solution of this particular problem, so it will be unfair from me to write about it, and spoil the fun of others.

It is a really entertaining book, even for me who do not like too much the field of probability. In that book I remember a problem referred to a drowry which almost obsessed me, I did spend hours and hours mulling over it, in my commuting driving, awaiting my flight in airports,or just awake in my insomnia,it was really challenging experience, so if you consider appropiate post it, I believe you should get a lot of attention.


  Alert | IP Printer-friendly page | Reply | Reply With Quote | Top
Owen
Member since Nov-11-05
Nov-17-05, 09:09 PM (EST)
Click to EMail Owen Click to send private message to Owen Click to view user profileClick to add this user to your buddy list  
2. "RE: Fun probability question"
In response to message #1
 
   Oh, yes, I remember that dowry problem, too. What a great problem! I recall that the final numerical answer to the problem was quite unbelievable, even when one read the solution. Unfortunately, I am out of the country until January, so I don't have access to the book. When I return, if no one else has posted it, I will. There are actually quite a few good problems in that book; maybe Alex could consider putting a few more of them on his Probability page (he already has Buffon's Needle problem there).


  Alert | IP Printer-friendly page | Reply | Reply With Quote | Top
alexbadmin
Charter Member
1691 posts
Nov-19-05, 00:02 AM (EST)
Click to EMail alexb Click to send private message to alexb Click to view user profileClick to add this user to your buddy list  
4. "RE: Fun probability question"
In response to message #2
 
   Just to put things in perspective, Buffon's problem came from a different place. Which is not to say that F. Mosteller's book does not deserve a reference. I have its Russian translation from 1985.

Now, the dowry problem. Translating back, it may look like this:

In search for a royal advisor, the king offers candidates a hand of a lady in attendance with the highest dowry. There are 100 young ladies, all with different dowries. The amounts of dowries are written on tickets and thoroughly mixed. A candidate draws a ticket and gets to decide whether the amount he read is the highest. In case he makes the right decision, he gets a wife and the dowry. In case he makes a wrong decision, he leaves empty handed. However, he is not obligate to make a decision at all, but is allowed to draw another ticket instead. Now again, he can either make a decision and face the consequences as before, or draw a third ticket, and so on. What is the best strategy?


  Alert | IP Printer-friendly page | Reply | Reply With Quote | Top
mr_homm
Member since May-22-05
Nov-22-05, 09:58 AM (EST)
Click to EMail mr_homm Click to send private message to mr_homm Click to view user profileClick to add this user to your buddy list  
5. "RE: Fun probability question"
In response to message #4
 
   Just to clarify the rules, is it correct to assume that the tickets are not returned after they are drawn? Also, should I assume that the candidate cannot later declare that an earlier ticket was the highest, i.e. he has to make a yes or no decision about the current ticket only? Without these assumptions the puzzle seems too easy.

If the tickets are returned, he can simply keep drawing them for months if necessary until he is certain he has seen them all, and then wait for the highest one to come up again -- an easy solution.

If the tickets are not returned and he can choose an earlier ticket, he can simply take tickets until he has seen them all, and then choose the highest -- an even easier solution.

I haven't started thinking about the actual puzzle yet with these assumptions included.

--Stuart Anderson


  Alert | IP Printer-friendly page | Reply | Reply With Quote | Top
alexbadmin
Charter Member
1691 posts
Nov-22-05, 10:01 AM (EST)
Click to EMail alexb Click to send private message to alexb Click to view user profileClick to add this user to your buddy list  
6. "RE: Fun probability question"
In response to message #5
 
   >Just to clarify the rules, is it correct to assume that the
>tickets are not returned after they are drawn? Also, should
>I assume that the candidate cannot later declare that an
>earlier ticket was the highest, i.e. he has to make a yes or
>no decision about the current ticket only? Without these
>assumptions the puzzle seems too easy.

Once a decision about a ticket was made, the ticket is discharged and is never considered again.



  Alert | IP Printer-friendly page | Reply | Reply With Quote | Top
alexbadmin
Charter Member
1691 posts
Nov-18-05, 03:10 PM (EST)
Click to EMail alexb Click to send private message to alexb Click to view user profileClick to add this user to your buddy list  
3. "RE: Fun probability question"
In response to message #0
 
   >Here is a fun problem for those of you haven't seen it. I
>believe it may be found in the Dover book entitled something
>along the lines of "50 Probability Problems" (a great little
>book).
>
>You, Annie, and Bob will be participating in a truel (a duel
>with 3 people). The three of you will take turns firing one
>shot from your gun; once a person is hit he/she is out of
>the competition. You have the advantage of going first, but
>you only hit your intended target 30% of the time. Annie
>goes next, and she never misses. Bob shoots third, and he
>hits his intended target 50% of the time. What should your
>strategy be as the first shooter? (Assume a rotation of
>You, Annie, Bob, You, Annie, Bob, etc. until one person is
>hit, afterwhich the two remaining competitors take turns
>shooting.)

See

https://www.maa.org/mathland/mathtrek_1_26_98.html

for a discussion and a couple of additional references.


  Alert | IP Printer-friendly page | Reply | Reply With Quote | Top

Conferences | Forums | Topics | Previous Topic | Next Topic

You may be curious to have a look at the old CTK Exchange archive.
Please do not post there.

|Front page| |Contents|

Copyright © 1996-2018 Alexander Bogomolny

Search:
Keywords:

Google
Web CTK