Glassdoor Interview Question: "Suppose you had eight identi... |

Interview Question

Associate Account Manager Interview Chicago, IL (US)

"Suppose you had eight identical balls. One of them is

  slightly heavier and you are given a balance scale. What's the fewest number of times you have to use the scale to find the heavier ball?"

Interview Answer

3 Answers


Group 1 Group 2
A B C D E F | G H

Weigh ABC vs DEF. If (for example) ABC is heavier then weigh A vs B. If A>B then you have your answer, if A=B then C is the heavier ball. Same scenario follows for DEF.

If ABC = DEF then weight G vs. H and you are done.

2 is the most efficient way to do this.

MB on Jul. 3, 2019

Really good lessons to get into top tech companies:

Anonymous on Oct. 15, 2019

One or more comments have been removed.
Please see our Community Guidelines or Terms of Service for more information.

Add Answers or Comments

To comment on this, Sign In or Sign Up.