Allstate Interview Question: You have seven balls and a tw... | Glassdoor

Interview Question

Actuarial Analyst Interview(Student Candidate) Northbrook, IL

You have seven balls and a two sided scale. all weigh the

  same but one. In two measurements find th odd bal

Interview Answer

3 Answers


I'm pretty sure that you have to know if the odd one is heavier or lighter than the other ones to do this in 2 measures

Anonymous on Jan 17, 2012

It took me like 2 minutes to figure this out. I'm not fond of word problems either lol. I'm assuming this is correct.

Okay put 3 balls on each side, hold onto 1. If one side is already leaning down with more weight, I know the heavier ball is that group of 3. If both sides are equal on the scale, then I’m already holding onto the heaviest ball and their is no need to continue.

Okay, assuming one set of 3 balls is heavier, clear off the other lighter side and repeat the process with the heavier set of 3 balls. Again hold onto 1 ball, put 1 ball on the left and 1 ball on the right. If one ball is leaning down, that’s the heaviest ball. If they are both equal on the scale, then I’m holding onto the heaviest ball.

Paul T. Fischer on Mar 15, 2013

Just wanted to state that you can do the same thing / process for finding the lighter ball, you would just keep the lighter balls on the scale and remove the heavier ones or if there equal you know you're holding onto the lighter ball.

Paul T. Fischer on Mar 15, 2013

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