Prelims · 8 Mental Ability · 8.15 Logic puzzles and problem solving

8.15.2 Weighing, balances and counterfeit-coin puzzles

A two-pan balance has three outcomes (left down, right down, level), so each weighing can cut the suspects to one-third — which is why powers of 3 run through every counterfeit-coin and weights puzzle.

  • APPSC Group 2 · Prelims
  • Standard level
  • 7 min read
  • Full course

Key terms

  • balance puzzle
  • counterfeit coin
  • fake coin
  • minimum weighings
  • powers of 3
  • powers of 2
  • weights on both pans
  • fake bag puzzle
  • balance equations
  • heaviest and lightest
  • twelve coins

What this note covers

  1. Core factsFoundation
  2. ExplainedStandard
  3. DeeperAdvanced
  4. Common trapsFoundation
  5. Quick revisionFoundation

Read the full note in the app. It is part of the APPSC Group 2 full course in Medha AI. Free in the app: the first chapter of each topic.

Read the full note in the app Mental Ability questions with answers

All Logic puzzles and problem solving notes · APPSC Group 2 syllabus · APPSC G2 Prelims Mock 1 with answers · Start free

Medha AI writes its own notes and checks them against the sources listed. Medha AI is an independent preparation service. It is not affiliated with, endorsed by or connected to APPSC, TSPSC, MPSC, UPSC or any other commission or government body.