Weighing Trouble: Find the Set with 5kg Balls

  • Context: High School 
  • Thread starter Thread starter ashishsinghal
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Discussion Overview

The discussion revolves around a problem involving identifying a set of balls that weigh 5kg among multiple sets, where most sets contain balls weighing 10kg. The focus is on the use of a digital weighing machine to determine the correct set with a single measurement.

Discussion Character

  • Exploratory, Conceptual clarification, Debate/contested

Main Points Raised

  • One participant presents a scenario with 10 sets of balls, where 9 sets contain 10kg balls and 1 set contains 5kg balls, and asks how to identify the set with the lighter balls using a digital weighing machine once.
  • Another participant references a previous thread, suggesting there may be established methods or solutions related to the problem.
  • There is an exchange about the familiarity with similar problems, indicating that some participants may have prior knowledge of related riddles or puzzles.

Areas of Agreement / Disagreement

The discussion does not reach a consensus on the solution to the problem, and there are indications of differing levels of familiarity with similar types of problems among participants.

Contextual Notes

Participants do not provide detailed methodologies or solutions, leaving the problem's resolution open-ended and dependent on individual reasoning.

Who May Find This Useful

Individuals interested in problem-solving, logic puzzles, and mathematical reasoning may find the discussion relevant.

ashishsinghal
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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?
 
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https://www.physicsforums.com/showthread.php?t=100534
 
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.
 
You got it right. Did you think of it or you knew it. Even for the "Two Doors". You seem to be a professional.
 
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 :smile:
 

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