Goldman Sachs Interview Question: Given 9 ball with only one di... | Glassdoor

Interview Question

Analyst/Developer Interview London, England (UK)

Given 9 ball with only one differ in weight, how to find

  out by measuring them only twice?

Interview Answer

4 Answers


Take 3 balls each. Weigh by keeping 3 on one side and three on other and keep the remaining 3 aside.

1. If the weigh comes as equal u know the ball with diff in weight is in the three kept aside. So again weigh by keeping one of the three on one side and one on other .
If equal the third one is the one that differs in weight else ur weighing machine will tell u the one which differs in weight.

2. If initial weighing is not equal follow step one for the weigh which shows the diff

prachi on Jul 19, 2011

Drop them from a sufficient height. If 8 balls land first your 9th is the lightest, if 1 lands first, it's heavier than rest. 1 go, do I get brownie points?

CP on Mar 1, 2012

The above is so stupid...even Galileo knew that couldn't happen...and that was over 300 years ago...

wow so so stupid... on Mar 9, 2013

In theory, if you do the experiment in air, it is possible.

haha on Sep 12, 2013

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