Ericsson-Worldwide Interview Question: I had not expected to be aske... | Glassdoor

Interview Question

Senior Software Engineer Interview Durham, NC

I had not expected to be asked logic questions, which made

  me nervous. The first one was a weigh nine items on a balancing scale to find the odd one out in the fewest scale uses

Interview Answer

3 Answers


Split them into three groups of three, weigh two to determine the odd set out, then split that stack of three into three sets of one, and weigh two to find the single one out, requiring only two scale uses.

Interview Candidate on Mar 24, 2009

The above strategy works only if you know whether the odd item is lighter or heavier. If you do not know how it differs, you will need more scale uses.

Anonymous on Nov 1, 2010

111-111-114 <--- By weighing any of two sets, you get 114.

1-1-4 <----- By weighing any of two, you can find out 4.

Node on Feb 16, 2013

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