On Tue, Sep 8, 2009 at 7:16 PM, Kiran K Karthikeyan < [email protected]> wrote:
> > But you can tell a lot with the way they approach the problem. For e.g. if > a > candidate puts 6 balls on each pan for the first weighing without realizing > its a waste i.e you learn nothing new really except that one side might > have > the heavier and the other the lighter - without eliminating any balls or > knowing which of them have the standard weight with which to compare > against. > Actually I can get there in four weighings by starting with six balls on each scale. (It doesn't lead to an immediate elimination, but you get two pieces of info on the next weighing -- which group of six balls has the errant ball, and whether it's lighter or heavier. You need two more weighings after that.) Why is this approach wrong if you can't get there quicker than four weighings? -- Amit Varma http://www.indiauncut.com
