1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Weighing marbles

  1. Apr 1, 2007 #1
    i give you 12 marbles. 11 of them are identical. the 12th one looks the same, but is either heavier or lighter than the other 11.

    you also have a balance scale. the kind that weighs things on both sides - and if one side is heavier, it tilts down.

    you are allowed only 3 weighings.

    tell me which ball is the oddball, and whether it is heavy or light.
     
  2. jcsd
  3. Apr 1, 2007 #2
    This was just posted one or two months ago. In fact, a search for "balance" in the Brain Teasers forum shows that it is posted quite frequently. I wonder what it is about this particular puzzle that makes it so popular.
     
  4. Apr 1, 2007 #3
    sorry about that. i did look thru the first page for marbles, and did not see anything. i didnt look more closely at the rest of the wording.

    to answer your question - it took me a long time to figure it out. it has been one of the best puzzles that i have worked on for a long time.
     
  5. Apr 1, 2007 #4
    i was just about to post the one about crossing the river with cannibals, but i find that this has also been posted. it only took me an hour or so to figure that one out. i found the marble one much more difficult.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Weighing marbles
  1. Weighing the balls (Replies: 16)

  2. Weighing the Human Head? (Replies: 19)

Loading...