You have ten boxes; each contains nine balls. The balls in one box weigh 0.9 kg; the rest weigh 1.0 kg. You have one weighing on an accurate scale to find the box containing the light balls. How do you do it?


--- James.

James I think its a long time that nobody has placed the answer.I tried my best but could not get it.Can you let me know the answer and the way for solving this.

Here is the solution,

Pick one ball from the first box,2 from the second,3 from the third and so on.

we have 55 balls. Now weigh them on an accurate scale

if the total weight is 54.9 kg then only one ball among 55 balls is a lighter one which means Box No 1 has light weight balls

if the total weight is 54.8 Kg then two balls are light weight balls which implies box 2 has light weight balls
and so on.

-- James.

James. It was a very detailed and good explanation. I will try to solve problems having this also as a tip. Thanks for your explanation

Hello the question tells every box has 9 balls ...then how can u take 10 balls from the 10th box ....

So the answer is
take 1 ball from 1st box,2 from 2nd so on till 9 from 9th box
Now if the total weight is 45 then obviously the 10th box should be having 0.9kg balls
else if the weight is 44.9 then the first box
else if 44.8 then the second box so goes the solution .......