The maximum number of balls for which you can solve the problem in 4 weighings is in fact 39.
Actually, you can do up to 40 balls in four weighings, not just 39.
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Posted 24 March 2010 - 09:01 PM
The maximum number of balls for which you can solve the problem in 4 weighings is in fact 39.
Posted 30 September 2010 - 06:40 AM
Posted 13 February 2011 - 12:44 PM
Posted 16 May 2011 - 02:11 AM
tambay, i think you were finding out how to tell if that specific one is lighter or heavier, and even then, you'd have to have more steps to do that. the next step from case 1/2 is to take the other ball and see if it balances with one of the balls from case 1.if it does, then you have to try the other set of 3 to find out if that specific one is lighter or heaver by repeating the step that lead to case1/2.I have a shorter solution.
Put six balls on each side of the scale. Whichever is lighter, the lighter ball is in that group of six.
From these balls, put three balls on each side of the scale.
Whichever is lighter, the lighter ball is in that group of three.
From the three balls, put a ball on each side of the scale.
Case1: If the scales balance, the third ball is the lighter ball.
Case2: If one is lighter, then that is the ball...
Posted 07 June 2011 - 01:05 PM
Knowing what the site admin said, you could just rephrase this asI have a shorter solution.
Put six balls on each side of the scale. Whichever is lighter, the lighter ball is in that group of six.
From these balls, put three balls on each side of the scale.
Whichever is lighter, the lighter ball is in that group of three.
From the three balls, put a ball on each side of the scale.
Case1: If the scales balance, the third ball is the lighter ball.
Case2: If one is lighter, then that is the ball...
Posted 08 June 2011 - 03:52 AM
I have a shorter solution.
Put six balls on each side of the scale. Whichever is lighter, the lighter ball is in that group of six.
From these balls, put three balls on each side of the scale.
Whichever is lighter, the lighter ball is in that group of three.
From the three balls, put a ball on each side of the scale.
Case1: If the scales balance, the third ball is the lighter ball.
Case2: If one is lighter, then that is the ball...
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