Brain teaser Interview Questions | Glassdoor

# Brain teaser Interview Questions

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## Brain teaser Interview Questions

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Jan 21, 2010

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Aug 12, 2010

### Associate at Capco was asked...

Apr 25, 2010
 Let's say you have 10 bags of nails, and each nail weights 10g. You also have a scale upon which you can weigh a combination of the bags or nails from the bags once. You know that one of the bags is off by a certain amount of grams, but you don't know which bag or by how much. How do you find out, with one weighing, which bag it is?10 AnswersNumber the bags 1 through 10. Take 1 nail from bag 1, 2 nails from bag 2, and so on. Take those 55 nails, which should weight 550g, and place them on the scale. If the weight differs from 550g by a certain amount, then that tells you which bag it is and how much it's off by.If each "nail weights 10g" as posed in the problem the ONLY weight you will get is 550g. My Idea is the instructions state "can weigh a combination of the bags or nails from the bags once." Place bag on scale result should = 100g, add bag 2 = 200g ect. when you add a bag and the result = less than the 100g, result = bag number and weight and difference. As you have continually adding weight is counts 1 time.Who cares? If you run out of nails go get some more.Show More ResponsesYou guys are doing this wrong. This is a twist on a very old problem, that actually has to do with twelve balls and can use the scale only three times. The trick is to divide the bags into smaller groups of 3, and see in which direction the bags move. It's easier if you draw it out. It is from "games for the super intelligent" by James Fixx.If I can only weight them once... then I'd put all the bags on, one weigh in and take the bags off one by one. The weight should go down by 10g each time until you get to the bag which is off. Technically it's one weigh in at the beginning and the rest are clearing the scale.Take all the nails out of the bags weigh them divide by 10. The number wont come out even, bag up your nine even piles, then the last bag you have is the one that is "short".This is a stupid question to use in an interview. Presumably by the time people get to this level, they've already taken the SAT and GRE, the latter of which includes a logic section. Test people on things that are going to matter for the company's bottom line, not a logic problem.I agree with kgar 79. The problem states that you can weigh the nails individually, which means you can take them out of the bag. Once you do, you'll be able to see which bag has more or less nails than the others. Since the nails all weigh the same, any variation in weight, will be determined by whole nails.Simple, and it can be done without weighing anything. Count the number of nails in a bag and multiply the number by 10g.kgar79 got it right. Just dump out all the nails, put the same number of nails in nine of the bags,their weight is now 10g x the number of nails per bag, then put the rest of the nails in bag #10. Then weigh it and now you know which and by how much it is off. You don't actually even need the scale.

### Sales Strat Intern at Goldman Sachs was asked...

Mar 17, 2013

May 15, 2009
 What is the square root of .01?8 Answers.3167 - Just memorize it, it's very common.I think you mean the sqrt of 0.1, not 0.01. The sqrt of 0.01 is 0.1.Not to be a fuddy-duddy, but .3162 would be closer. (If you're going to take it to 4 decimals then you should use the closest 4th decimal.)Show More ResponsesAnswer: 0.1 assuming my 2 SCI calculators and my manual calculations are correct Comments: 1- 0.3167 is the square-root of 0.1 not 0.01 2- Don't tell you interviewer he is wrong. You want the job don't you? 3- You actually need to use a 5/4 round-off using the 5th place for a more accurate 4th ( I think that's what you meant to say)0.01 is the same as 1/100 and if you take the square root of the top and bottom, you get 1/10 or 0.1.The square root of 0.01 is neither 0.1 nor 0.3162. The square root of 0.01 is +0.1 AND -0.1 (Negative 0.1). The negative root is frequently overlooked.Isn't it prime already? So its sq rt is 0.01. I'm so confused!actually, square roots are always positive. the definition of a square root is that it's an absolute value. i.e. sqrt of (-1)*(-1) = |-1| = 1 My real response to this topic though is that I dread such silliness in interviews. In my current position I was asked a stupid question in a 5-on-1 interview and basically said what I thought about the question but still got the job - so maybe that was the correct answer. Hope I don't ever find myself desperately needing a job and having to endure this silliness again.

Mar 5, 2009

Jan 27, 2011