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Comment by DanBC | Hacker News Reader

No-one is interested in the number you come up with. They're interested whether or not you have a process you use to come up with that number.

Ask some people how many golfballs fit in a bus. They'll be stumped. They'll have no idea how to proceed. They'll just stop, and look at you, and flounder.

Ask other people and they'll have a problem solving process. They'll define the problem; they'll gather information; they'll make assumptions (and note the dangers of assumptions) and then they'll start to work out a rough solution. The number that plops out the end is not relevant. Unless your process comes out with a number that is clearly nonsense ("5" or "27 billion") and you ignore that.

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> No-one is interested in the number you come up with. They're interested whether or not you have a process you use to come up with that number.

Then ask, "How would you figure out how many golf balls fit in a bus?" This circuitous way around finding out what you want is anathema to most techie types anyway.

My problem with these brainteaser type questions is the interviewer (in my experience) NEVER has had the experience or know-how to interpret the answer; all they have been able to do is get a level of "ah, interesting" type "gut feel" from it. If I'm interviewing with someone who's got the background to be able to analyze what I'm actually thinking, fine, but to date, I've not seen it.

This.

The most important takeaway from a face-to-face interview for me has always been to gauge a candidates general problem solving ability. When developing, you'll constantly be solving problems that are new to you, in areas you may not be familiar with.

The most important general problem solving skill is the ability to eliminate problems entirely so that you don't need to come up with a solution at all.

I think it's prudent to know the etymology of the word problem, whose origin is in "proballein", which literally means "thing thrown forward", much like a hot potato. And like a hot potato, the easiest solution is to throw it forward until it cools down. i.e. it comes to rest with someone who no longer sees it as a problem.

Handled elegantly and diplomatically, the "it's not my problem" approach to eliminating problems is a perfectly acceptable strategy, especially when you poorly understand the problem and the benefits of finding a solution. Eventually, if it is a problem worth solving, it will come to rest with the person who sees an opportunity in solving it and is equipped to do so. In fact, this is essentially the very basis of all rational economic activity.

Because we presume that an interviewee is desperate enough that they won't give the "honest" answer - well, I'll google that and see if I can't find someone else who has already found the answer.

Seriously, between Google and Wolfram Alpha, do you think that any of these inane questions can't be answered within a reasonable level of proximity?

Don't believe me? I just googled "golf balls in a school bus" and had a page full of answers in seconds including how they solved it as well as the number. https://www.google.com/search?source=ig&hl=en&rlz=&#...

Better, why not ask me to pseudo-code a problem you've faced recently? Wouldn't that tell you a LOT more about whether my skills and your needs align?

Go use Google and Wolfram Alpha to find the answers to "how many fashion items are for sale on the internet?"

If you can do that, I'm truly impressed by your google-fu. Also, as I said, the fashion items question is a problem I faced at my last job.

I highlighted your question, right-clicked and chose to Google it, and it was answer number 3 on the returned results. I suspect Alpha would give more useful detail, but then I really think that wasn't what you were looking for.

Slightly more seriously, going to Google first for ANY such problem would highlight both what is already known about the issue, and profitable answers to look for further information.

Then why wouldn't you ask a real-world question like that, rather than a stupid one about filling a bus with golf balls?

> Seriously, between Google and Wolfram Alpha, do you think that any of these inane questions can't be answered within a reasonable level of proximity?

Using Google? 3 in 600 searches used the + operator, and of those 2 were wrong.

Saying "I would understand the problem, I would work out a suitable search query, I would use available resources, I would evaluate the responses I got; here's the result when I used a typical question like this".

> Ask some people how many golfballs fit in a bus. They'll be stumped. They'll have no idea how to proceed. They'll just stop, and look at you, and flounder.

Because, as ebbv said, there is absolutely no way they can get a decent level of accuracy that would be useful for any kind of purpose. Any estimate in such a situation would be thrown away as soon as Google and other resources are available. Therefore they effectively cannot answer the question, and the question is useless.

Can I just say "I assume it's about 2000." and be done with it? I mean, that's a good enough estimate when we're not actually going to be putting golf balls on buses and are just chatting about it.

The purpose[1] of an interview (for the interviewee) is to get the job.

The purpose of the question is[2] to gauge the interviewee's ability to solve problems.

With those constraints your approach would appear to be sub-optimal. Sometimes in life we have[3] to jump through hoops to get what we want.

[1] Primary purpose; there are other things, such as deciding whether the company is a terrible place or full of idiots or etc.

[2] Should be; I accept that maybe many people have heard about these questions and think they're the right thing to ask but have no idea of the purpose.

[3] Or we decide that hoop jumping is not for us and we reject all hoop jumping and politely decline the job.

The hoops are invisible in this case.

It's a matter of putting on a show for the interviewer. But we don't know what kind of show. A show where we make assumptions about things? or ask questions? A show where we try to get as 'real-world' an answer as possible? or one where we assume things to make our lives easier? Why not just assume it's a toy bus and nothing can fit in it? Is that a clever and funny time-saving technique, or am I mocking the interviewer?

But yeah, the candidate has to do what he has to do if he needs a job. I think that's what you're saying anyway.

> they'll make assumptions (and note the dangers of assumptions)

So is it OK to make assumptions or not?

I agree with all your points, but also think one must be circumspect when applying this sort of question.

You're right, some people, when faced with a question like this, will flounder. Maybe sixty percent of the population. The rest will all solve it in a similar sort of way.

It's thus a bit of an "are you a complete idiot?" test, so by applying it you express an uncertainty over whether the person you're interviewing is a complete idiot. This is fine if you're interviewing fresh-faced undergraduates or something, not so good if you're interviewing someone with a long track record of success for a senior role.

I don't interview people all that often, and the circumstances are such that by the time someone gets in front of me I can take it for granted that they're not a complete idiot. Thus, I feel no need to apply this kind of test.

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