You are given 6 identical balls of same size and shape two of which are red. two white and two blue. It is known that one ball of each colour weighs 15 gm; while the other weighs 16 gm. Using a two-pan balance only twice how will you separate the balls of 16 gm weight?

(In reply to Simple method. by broll)

"Weigh red+white-vs-red+blue. If either side is heavier, that side contains the heavy red ball, and white = blue"

But the side with the heavy red ball might also contain the heavier of the white or blue ball which accompanies it. That is, the heavy side might have two extra grams rather than just one.

Posted by Charlie on 2013-01-10 02:29:41