Interview Question

Interview(Student Candidate)

How would you determine the heaviest marble among 9 marbles

  where 8 weigh the same and you can use the scale only twice?

Interview Answer

1 Answer


1st weighing pick any 6 marbles and weigh 3 vs 3 . If both are same , heaviest is in the remaining 3. Else heaviest is one of these 3. So after the first weighing we are left with 3 marbles. 2nd weighing take any 2 and compare them. If they both weigh same then the remaining one is the heaviest. Else you know it.

rkt on Apr 26, 2012

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