Weighing Trouble: Find the Set with 5kg Balls

[ashishsinghal]

suppose you have 10 sets of balls containing 10 balls each. out of these 9 sets have all balls weighing 10kg (individually) and 1 set has 5kg balls. You can use the digital weighing machine once. how will you wind out which set has 5kg balls?

 

[ashishsinghal]

Please read this before answering:

https://www.physicsforums.com/showthread.php?t=100534

 

[micromass]

Spoiler

I'd pick 1 ball from the first ball, 2 balls from the next, 3 balls from the next, and so on. Then I'd weigh them, and the result would tell me which balls are lighter.

 

[ashishsinghal]

You got it right. Did you think of it or you knew it. Even for the "Two Doors". You seem to be a professional.

 

[micromass]

Well, the two doors was something I knew of before. But I don't think I've solved this one before. It was a fun riddle though