Jump to content


Welcome to BrainDen.com - Brain Teasers Forum

Welcome to BrainDen.com - Brain Teasers Forum. Like most online communities you must register to post in our community, but don't worry this is a simple free process. To be a part of BrainDen Forums you may create a new account or sign in if you already have an account.
As a member you could start new topics, reply to others, subscribe to topics/forums to get automatic updates, get your own profile and make new friends.

Of course, you can also enjoy our collection of amazing optical illusions and cool math games.

If you like our site, you may support us by simply clicking Google "+1" or Facebook "Like" buttons at the top.
If you have a website, we would appreciate a little link to BrainDen.

Thanks and enjoy the Den :-)
Guest Message by DevFuse
 

Photo
- - - - -

yet another balance puzzle


  • Please log in to reply
7 replies to this topic

#1 phil1882

phil1882

    Senior Member

  • Members
  • PipPipPipPip
  • 543 posts

Posted 24 October 2013 - 06:16 PM

i bleive this challange may have been posted before, never the less here goes.

you have 3 wieghing scales, a normal scale that gives the correct result, a reverse scale that gives the oppisite result, and a random scale that gives, well you guessed it, a random result.

you have 4 normal coins and 4 heavy coins. your task however is to simply identify which scale is which with the fewest weighings, and you don't intially know which coins are which either.

 


  • 0

#2 ThunderCloud

ThunderCloud

    Advanced Member

  • Members
  • PipPipPip
  • 102 posts
  • Gender:Male
  • Location:New England

Posted 24 October 2013 - 06:53 PM

Spoiler for If these are balance scales...


  • 0

#3 jamieg

jamieg

    Newbie

  • Members
  • Pip
  • 17 posts
  • Gender:Male

Posted 24 October 2013 - 06:55 PM

I don't see how this is possible. Theoretically the random scale has a small possibility of replicating either of the constant scales indefinitely just by random chance. If it randomly gives the correct answer the first ten times, any observation on it will be the same as if it were the truth telling scale; same with if it's a hundred or infinite times. 

 

Spoiler for If I'm correct...


  • 0

#4 dgreening

dgreening

    Junior Member

  • Members
  • PipPip
  • 74 posts
  • Gender:Male
  • Location:Maryland [DC area]

Posted 24 October 2013 - 08:40 PM

I think you are both on the right track.

Spoiler for

  • 0

#5 shammaa

shammaa

    Newbie

  • Members
  • Pip
  • 2 posts

Posted 24 October 2013 - 10:04 PM

will the reverse scare read correctly if they are equal? 


  • 0

#6 phil1882

phil1882

    Senior Member

  • Members
  • PipPipPipPip
  • 543 posts

Posted 24 October 2013 - 10:39 PM

yes. the random scale may or may not. i tend to agree. could ptontially be infinite wieghings.


  • 0

#7 bonanova

bonanova

    bonanova

  • Moderator
  • PipPipPipPip
  • 5891 posts
  • Gender:Male
  • Location:New York

Posted 25 October 2013 - 03:25 PM

To make it solvable, change the random scale into an alternating scale.


  • 0
The greatest challenge to any thinker is stating the problem in a way that will allow a solution.
- Bertrand Russell

#8 jamieg

jamieg

    Newbie

  • Members
  • Pip
  • 17 posts
  • Gender:Male

Posted 27 October 2013 - 05:46 AM

To make it solvable, change the random scale into an alternating scale.

 

Spoiler for In that case...


  • 0




0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users