Libra scales (Originally uploaded by Onkel Ulle)

I am working on this puzzle today and I thought it would be quite interesting for other who are looking for mental workout.

You see 12 balls of equal size and shape, but one of them is either slightly heavier than the others.

Q1 – Can you find the odd ball and determine with just 3 weigh-ins on a balance scale?

Try it out – http://members.aol.com/kmgames/oddball/12balls.htm

Q2 – If you have to do this exercise 1000 times, on average, how many times do you need to use the scale for each trial? Can you find a method that would use the scale even fewer times?

You can work it out for yourself or post it as a comment on my blog.

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I think you can also find the ODD ball even if u dont know its heavy or light. Knowing its heavy its easy to find out. Just weigh four balls a side. Whichever side is heavier contains the heavy ball.If the wmachine balances the other set of ball contains the heavy ball.Then weigh two a side.Again which side is heavy contains the heavy ball.Lastly weigh the two balls. Whichever is heavier is ur BALL!