
Why I ask "how many golf balls fit on a bus?" in job interviews - yummyfajitas
http://www.chrisstucchio.com/blog/2012/why_i_ask_fermi_problems.html
======
v0cab
The problem is, talented people (some of them, not all of them) are not
interested in ridiculous problems like this. It comes off as making the
applicant jump through a hoop and watching them squirm for your own amusement,
rather than as anything productive. No-one's interested in golf balls on
buses, because filling buses with golf balls is a waste of time. Talking about
it seems a waste of time.

And the question is stupid. Buses are different sizes and of different
designs, you know. We have double-decker buses in the UK.

If you must use this class of problem, at least make it more related to your
field or narrow down the kind of bus and what furniture is on it. And explain
to the applicant _why_ you would ask a question like this. "We want to see how
you think" isn't an adequate explanation.

------
ebbv
..and I will no longer be interested in the job if you think answering a
question like that is a worthwhile use of my time, or yours.

It's trivially easy to figure out how to calculate a rough number. I'd go so
far as to say blatantly obvious. It's also a waste of time to actually do it.

When it comes to the real world, an estimate that rough, based on no actual
data (since the actual dimensions of a golf ball or the hypothetical, poorly
defined bus are not available), is not something I'm _ever_ comfortable acting
on. In reality, you can always come up with better data than that.

~~~
DanBC
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.

~~~
undantag
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.

~~~
EwanG
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=&#...</a><p>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?

~~~
yummyfajitas
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.

~~~
EwanG
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.

------
jroseattle
I agree with the need to assess one's ability in Fermi-style problem solving,
but I find fault with using non-sensical information for the topic. Seriously,
golf balls on a bus? Why not ask about a relevant problem to be solved?

For me, an interview is a two-way street, and a company can most certainly put
itself out of consideration with these types of questions. The biggest issue I
find with these esoteric-problem-analagous-to-something-relevant types of
interview questions is that they usually send a negative signal about the
company. I immediately think of gamesmanship, trick questions, watching
candidates squirm, or about a dozen other things that I find have nothing to
do with the entire reason I might consider joining a company.

While the interviewer's intentions sound very noble, I find the means to the
end more risky than useful.

~~~
planetguy
_Seriously, golf balls on a bus? Why not ask about a relevant problem to be
solved?_

Asking about an irrelevant problem makes it clear that this question is about
your logical process and _not_ about your knowledge related to this job. It's
a way of isolating variables.

The actual golf ball/bus question is a bit too much of a cliche to actually
use, though. I'd rather ask how many raccoons you could put in a battleship.

~~~
jroseattle
Oh, I get the point the interviewer wants to reach -- using size estimation
questions to gain an understanding of one's logic process. But as a method of
achieving that goal, I've found it's a poor instrument.

Suppose candidate #1 is unimaginative and cannot offer a reasonable response.
Suppose candidate #2 says "well, a golf ball is such and such size, and there
is empty space around each ball, and the bus is such and such size....."

What, exactly, have we learned here? In my experience, nothing.

Having gone through this cycle as both a candidate as well as hiring manager
(not my choice to use this line of questioning), the real-world results I've
found is little to no correlation between candidate responses and accurate
assessment of logic process. The false positive/negative outcomes were
significantly higher, and the success rate for candidates into the positions
we hired them for were mixed. Basically, these questions offered us nothing in
finding candidates who would be successful in the position for which we were
hiring.

If I were to ask a question such as this, it would be to gauge one's reaction
to the question (assuming it's a stressor) and how they react. The response is
nearly irrelevant. But I don't like the tone the question sets between myself
and a candidate, so I just don't resort to this as a means to achieving that
goal. There are better ways to get at that information.

------
ohyes
Clearly eggplant golf balls fit on a bus.

I always assume the reason that you ask these questions is because you don't
have anything interesting to talk about in the interview.

Interviews are as much a chance for a candidate to disqualify the
interviewer/company because they asked stupid questions, as they are for the
interviewer to ask stupid questions.

You got me all the way out here, spending my valuable time talking to you, and
all you can come up with is a lame question about golf balls? Sell your
company to me. Show me that you are excited about what you are doing. Talk to
me about what problems you've been solving lately and try to see how I would
go through the process of solving those problems. Sure there are NDAs and you
don't want to violate that, but programming problems are programming problems,
and if I am spending my time talking to you you can do me the favor of talking
generally about what you are doing and making it interesting for me.

~~~
huggyface
_Interviews are as much a chance for a candidate to disqualify the
interviewer/company because they asked stupid questions_

Is this really true? Generally candidates know far more about the company than
the company knows about the candidates. I think any notion that it's a meeting
of equal interests is self-empowered fantasy.

"as they are for the interviewer to ask stupid questions.*

I ask "stupid" questions of candidates. One of the reasons I ask those
questions is, quite honestly, because I want to exclude those people who have
an attitude about "stupid" questions. Those who can't professionally humor
simple questions are seldom the people anyone wants to work with.

And for the record the people who are really in a position to essentially set
the terms _we don't even interview_ (beyond meeting with senior management to
give them the sales pitch).

~~~
malandrew
Are you sure you aren't conflating "having an attitude about 'stupid'
questions" with "simply rejecting 'stupid' questions"?

It's possible to reject stupid questions in a way that is diplomatic and non-
douchy.

I'd think that being tolerant of accepting 'stupid' questions is as
undesirable as having an attitude about them. The former demonstrates
unproductive compliance, while the latter demonstrates unproductive social
behavior. Surely there must be an optimum point where someone can behave in a
way that demonstrates productive non-compliance, no?

~~~
huggyface
_It's possible to reject stupid questions in a way that is diplomatic and non-
douchy._

Absolutely, and that's how professionals deal with other professionals. The
comment that I responded to demonstrated significant _attitude_ about what
they called stupid questions (which are the Fermi problems).

An interview is not a skill discovery session -- ideally your resume and
online presence (e.g. github projects) has demonstrated that, along with, if
necessary, a practical test. An interview is getting to know how you think,
how you communicate, how you deal with people, how you approach problems, etc.
It is astonishing how many people _don't understand this_ , and thus don't
understand questions that aren't an autism-level focus on a person's specific
skill gamut.

Can you tell me what you believe your biggest weakness is?

~~~
ohyes
I don't have an attitude about answering 'stupid' questions if they are asked
in an honest manner. I have answered and asked many 'stupid' questions in my
lifetime and will answer/ask many more. Asking stupid questions is a part of
learning. You are reading far too much into my use of the word stupid.

My point is that if I agree to an interview, I would much rather have an
interesting technical discussion with one of your engineers than be asked
brain-teasers by someone from HR.

I would politely answer the question and would not dismiss it. However I find
the practice off putting in general.

Fermi problems are a game that give you an estimate of the person's thought
process. Another way to gain an estimate of a person's thought process is to
engage that person in intelligent conversation on just about any subject. I
much prefer intelligent conversation, as it can actually be quite pleasant.

My biggest weakness?

The interviewer clearly is interested in something contrived and job related.
But what are they looking for? Do I spin it and say how "my biggest strength
can sometimes be a weakness when..." Am I honest and tell them what my actual
job-related biggest weakness is?

If I just straight up tell you something like "I'm incredibly disorganized and
never show up when you tell me to," I'm clearly not going to get the job. You
don't get any points for honesty. Do you want something where the interviewee
has spun his biggest strength? It is dishonest but a better answer.

Asking my biggest weakness is really just you asking me 'What do I want to
hear.' Another game... I don't know you very well; how could I possibly answer
it? So there it is, my biggest weakness is reading your mind. :)

Or maybe my biggest weakness is over-analysis. In what context of the words
'biggest' and 'weakness' would you like this question answered?
Size/importance/grandeur/impact? Mental/medical/social/skill competency?

Literally speaking, it would probably be the oxygen supply on earth. It takes
up quite a lot of volume, and if it is removed I'm a goner.

edit: biggest weakness... grammar, punctuation.

------
hedgie
_I often do ask at least one of these questions on an interview. I don’t do it
because I care about a precise answer or whether you know the exact dimensions
of a golf ball. I care simply because if you can’t do Fermi calculations, you
can’t make long term architectural decisions. You’ll build a system which
handles 2x today’s load very nicely and which I need to replace in 2-3 years,
or you might overarchitect a system which can handle 1000x more load than I’ll
ever need._

...why not just ask a question about building a real-time monitoring system
itself and judge the responses there?

i would never pass this test. i would solve this problem using variables for
dimensions of the bus and a constant "packing factor" (or assume the optimal
cannonball packing and approximate the golf balls as spheres) and write an
express formula for the solution. then i would substitute in various constants
for the dimensions and adjust the packing factor to find a range of solutions.

the problem with the question is they want an intuitive solution. giving them
this formula and evaluating for a range of variables would just piss them off,
but it's the best way to approximate the answer of something that poorly
defined.

~~~
ajdecon
_i would never pass this test. i would solve this problem using variables for
dimensions of the bus and a constant "packing factor" (or assume the optimal
cannonball packing and approximate the golf balls as spheres) and write an
express formula for the solution. then i would substitute in various constants
for the dimensions and adjust the packing factor to find a range of
solutions._

Oddly enough, this was exactly how I was taught to solve Fermi-like problems
in my physics program. The point was not so much to be able to "intuit" the
answer as to learn how to find approximate solutions with little or no real
data. You could do this sometimes just with off-the-cuff estimates (as in the
piano tuner example in <https://en.wikipedia.org/wiki/Fermi_problem>), but
often enough we came up with approximate formulas and guessed at the
constants.

I haven't been in enough startup job interviews to know if actually doing
algebra would make them think less of me, but that would really seem pretty
dumb.

~~~
hedgie
that may be an unfair assumption on my part. i just assumed that when people
ask these abstract riddles, they're really looking for some way of testing
your intuition and not something this mundane and boring.

it really boils down to basic algebra with some constant fudge factors.
meanwhile, cs people have a host of sophisticated tools to estimate asymptotic
behavior for the worst, best, and average case, or error bounds on solutions
to NP complete problems as a function of the number of iterations of
approximation algorithms, or trade-offs when certain pre and post conditions
on the data influence the run-time of canonical algorithms (think searching).

the basic toolset of computer scientists is so advanced i guess i'm shocked
anyone would ask such a relatively simple problem when there are much better
ones out there.

~~~
ajdecon
Warning: I don't actually do web startups myself, so this is based on an
outsider's view of the field.

Computer science provides some really awesome ways to deal with algorithmic
problems... but for most startup-type applications, those problems only come
into play in a few places (if that). A cool time-management webapp might have
an interesting algorithm at its core that uses machine learning to auto-decide
what tasks are most important (making something ridiculous up), but the rest
of the app is basically just a shiny interface to a database.

I really doubt the problems of scaling a CRUD webapp (at less than Facebook
scale) lend themselves to good mathematical analysis. Even if they did, these
apps involve lots of third-party layers glued together to put together
interesting functionality, and those seem to change often enough that it's not
worth even trying detailed analysis.

So instead they do Fermi-problem estimates to figure out their basic scaling
relationships. Then you can decide how to plug things together, decide what
your basic resource constraints are (compute, memory, disk, bandwidth...) and
make it easy to add those resources when your customer base expands.

Edit to add: Thinking a little more, that's _exactly_ when you'd want a set of
approximate algebraic constraints, so you could decide how many customers-per-
EC2-instance you could serve and how that number might change as instance
count increased. Math, it's important.

~~~
hedgie
that's a good point.

at my large company i do this every day on the embedded system i work on,
which luckily is not a CRUD app. i guess i would hope they would ask me about
that XD

databases can get tricky. but you're right, if something complicated like a
bloom filter is used to solve subset-query it's probably in an third-party API
they grabbed somewhere that handles most of the difficulty.

------
pooriaazimi
I don't have a single clue how many fashion items are on sale at a given time,
not because I'm incapable of estimating it (even though I've never heard of
Fermi problems before), but simply because I have no _field knowledge_ about
online store business.

Give me a day to think/research if you really want to make sure I'm the right
guy for the job, because in the real life, I _have_ the luxury of not being
forced to come up with an answer in 3 minutes in a job interview (that would
very well change the course of my life).

With all respect, I think all your questions are irrelevant and are definitely
not a good metrics for hiring/filtering out candidates. For all means ask them
about clustered/non-clustered (to use MSSQL's terminology) indices or stuff
like that, but don't put them in a position like this one (they don't know the
answer, but given a few days they can give you a pretty accurate estimation).

~~~
yummyfajitas
I don't expect you to know the answer. I expect you to tell me how you would
research it.

An answer I like: "I'd search on amazon and a few other top fashion sites to
get per-vendor count, as well as some of the lower end."

At that point I'd tell them that ShopBop and Net-a-porter are two typical
bigger sites, and they each have about 20-50k items. I'd also point out there
is a longer tail of much smaller sites.

If your answer is 3M or 20M to my 10M, I don't much care. This isn't a
question with a definite answer, it's a question about whether you can think
on your feet and get started on poorly defined problems.

With me, it's a good sign if I'm asking you the poorly defined questions with
unclear answers. If I reach this point, I've already decided you probably know
_how_ to code, and I want to determine if you can figure out _what_ to code.

~~~
pooriaazimi
> _If I reach this point, I've already decided you probably know how to code,
> and I want to determine if you can figure out what to code._

Well, if that's the case, then it could be a good question.

However, you didn't state or emphasize that in your blog post and from what
I've heard, many companies ask such unrelated questions _first_ to filter out
completely hopeless candidates and then get to the _real_ interview (technical
questions), so I assumes this is what you meant, and I don't owe you an
apology ;-)

------
achy
This is dumb for one simple reason, It divides candidates based on an
arbitrary line that has only limited correlation to the desired split: Those
who fit your job requirements vs. those who do not. Instead, ask them to solve
a pertinent problem to your company. If they go down the wrong path, give them
a hint as to the right track and see how well they can grasp the new method.
Simple. OR even better ask the candidate to explain how they solved their own
last 'interesting' problem.

------
tomp
You're asking the wrong question. If an interviewer asked me "How many golf
balls fir on a bus?", the only sensible answer is "I don't know.", and if the
interviewer would expect anything else, I'd call him an idiot.

The correct question is "Estimate how many golf balls fit on a bus." I.e. I'm
not expecting the correct answer, I'm expecting an order-of-magnitude
estimate.

This specific question is however inappropriate even with the _estimate_
wording, since 1) busses differ (double decker, how many seats vs. standing
space, ...), and 2) golf balls are round. This means that the simple estimate
"how many 2 cubic inch things fit into a x * y * z box" (as attempted by
another commenter below) would produce wildly incorrect results.

~~~
stevewilhelm
Not to put too fine a point on it, but if you made this comment during an
interview, we wouldn't hire you unless looking for someone to sit alone in a
cubical to write device drivers.

------
rmATinnovafy
These type of questions belong in the "Weekly Puzzler" part of the Car Talk
radio show.

Honestly, what's the deal with them? Do you have an urge to somehow feel
smarter than the person you are interviewing?

Why don't you instead do the following:

Sit the programmer down and show him your source code. If he can make any
sense out of your spaghetti, then hire him/her. That's all you are looking
for, right? Someone who can understand what it is you are doing so he/she
canhelp you to do it faster.

No other industry has to deal with this nonsense. Imagine if auto mechanics
had to guess how many miles does the average Formula One engine piston travel
in a scheduled race. We would be riding around in bycicles because no mechanic
would take that.

------
daleroberts
Maybe I can add some context. I was the OP that started this whole discussion
about posing math problems / Brainteasers at interviews.

Out of the blue I got a call from a recruiter saying that bank X would like to
interview me for a quant role they have. They wanted to fast-track the process
so they booked me for 2.5-3 hours of back-to-back interviews. I was not
looking for a new job but I thought it might be good to talk to them and
explore leaving academia.

The first interview was with some quants who work for the hiring manager. They
tell me that they plan to have a technical talk with me and then follow that
with some math problems and brainteasers. At that point I respectfully
declined saying "I wasn't aware that I was going to be asked those types of
questions and I don't really believe they are a good hiring tool". The guy
tells me too bad, that's the way they hire now. I say fine and we carry on
with the first part of this session and have a technical talk.

We then come to the point that they want to ask me the math problems. I again
say that it's silly. They disagree. Then I say "For example, who's to say
you're not going to ask me problem A". They laugh. "followed by problem B, C,
D". They stop laughing. "Finishing with the problem about the expected number
of tosses of a coin to HH". They look at each other. "and who's to say that I
don't know the answers by heart. It's luck of the draw, maybe I know your
questions and maybe I don't and how would it reflect on me if I don't know".
The guy who had problems ready for me turned white. They quickly ended the
interview in a cordial way at that point and seemed to scramble to find the
next two guys to come and interview me. Probably because the interview
finished 30 mins earlier.

What they didn't realize is that I love these types of problems and that it is
a small community. I know a lot of people and remembered what questions they
had asked one of my friends. When they walked in the room, the guy had the
solutions written out on a piece of paper and with only a brief glance I knew
that I was going to get asked the same ones.

He had paper with the solutions face down during the whole interview but when
he left I have never seen anyone pickup a piece of paper in a more awkward
way. He did the whole fold in half as you lift thing.

------
alok-g
A bigger problem I have with these problems is that I do not feel motivated to
solve or even think about such problems. My internal reaction therefore always
is, why do I care how many golf balls fit, even if I do not say it out loud.

For whatever problem the interviewer poses me, I would like them to supply me
the context around that problem so I can see what is the benefit of solving
it. Solving it for the sake of the interview is not a valid answer for me.

There are a plenty of important problems to be solved for me to not waste a
minute on a useless one.

~~~
planetguy
Y'see, with that attitude I wouldn't hire you.

I don't want people who solve problems because they're important, I want
people who solve problems because they're intensely curious and just love
solving problems.

~~~
alok-g
Without knowing why the problem is important, you do not really understand the
problem yourself. Understanding the problem better is often even more
challenging than solving the problem (once understood). I have seen people go
circles around trying to solve the problem at hand without reaching the
solution that actually solves the problem, just because they did not
understand the problem correctly to begin with.

There indeed are curious problems. Estimating number of golf balls that can
fit into a bus is certainly not one of them. Try to come up with a curious
problem, then we'll talk.

------
antidoh
The author gives a reasonable example of the usefulness of this skill.

My problem with these questions is when they come out of a box delivered by
Cargo Cult Airlines. If you or your organization don't actually use these
techniques in the normal course of the job, then don't ask these questions.

"I just want to see how you think." OK, fair enough. After I've answered,
describe how I think, and compare and contrast that with how other candidates
think. My bet is that most people who ask this question have no idea how
anyone thinks, including themselves. Most people.

Column 7 of Programming Pearls (which can be read online, <http://netlib.bell-
labs.com/cm/cs/pearls/>) is an interesting exploration of the actual use of
this kind of exercise.

When you get a question about golf balls, don't just declare "Bogus." Consider
who's asking it, and whether they seem to know what they're doing with the
question.

The question is valuable to the candidate, and not just to identify lame
companies. Face it, most people just don't know how to interview, and if you
decide based on this, you're being a lazy interviewee. In rare cases, the
question might even expose a company with a clue.

Be open.

------
16s
It's pretty simple really. The answer does not have to be right. Just talk
your thought process through... how big is a golf ball... maybe 2 cubic
inches. I wonder how many cubic inches are on a bus... how big is the bus?
Well, it doesn't matter... assuming the bus is 20 feet long and 7 feet wide,
and 8 feet tall there would be X cubic feet in the bus some of which would be
taken up by seats and other things so we'll say X minus that to get the total
number of cubic feet that we can put the golf balls in. Now the question
becomes, "How many 2 cubic inch things can you fit into X cubic feet?"

That's it really. Just think it out and solve it like you would any other
problem. If you can't talk it out and sort of layout how you'd go about
solving it, then you're likely not a good candidate for some jobs.

------
sasha-dv
>Why I ask "how many golf balls fit on a bus?" in job interviews

Perhaps, you think that a direct question about realtime monitoring systems
isn't tricky enough?

~~~
gergles
I think this is really what it is. There's this trend in the valley of
everyone thinking they need ninja zombie pirate rockstar gurus who can solve
P=NP and interviewing accordingly, when they're really writing simple CRUD
apps and just need someone that knows how to do solid architecture and design.

Asking stupid questions like golfballs on a bus sends a signal of "we need
geniuses for some reason" and is intended to make the candidate think "wow,
the interview questions were so hard, everyone that works here must be really
smart!"

~~~
yummyfajitas
_...need someone that knows how to do solid architecture and design._

Solid architecture involves having an order of magnitude estimate of the load
you might expect and building accordingly.

How do you get your order of magnitude estimates?

~~~
gergles
"How would you scale a web service to handle 10 hits per second? 100? 1000?
10,000? 1,000,000?"

------
bediger4000
Short bus or long bus? A long bus is about twice as big as a short bus, here
in Denver, at least.

Also, with or without seats?

~~~
malandrew
I was thinking the same, but it'd be funnier to take it one step further:

"Short bus? Long bus? Double decker bus? Coach bus? VW Bus?" Since I'm not
sure of the relevance of the question, I choose a Matchbox Bus. The answer is
0. 0 golfballs fit in a matchbox bus. Enough bikeshedding. Let's move along to
questions that will more reliably assess skills I will be using on the job as
a software engineer."

"Bob Slydell: I'd like to move us right along to a Peter Gibbons. Now we had a
chance to meet this young man, and boy that's just a straight shooter with
upper management written all over him."

All questions like this would tell me about a candidate is that they have a
high tolerance for bikeshedding.

~~~
v0cab
> "Short bus? Long bus? Double decker bus? Coach bus? VW Bus?" Since I'm not
> sure of the relevance of the question, I choose a Matchbox Bus. The answer
> is 0. 0 golfballs fit in a matchbox bus.

You never know how far they want you to go with their game. This could mark
you as a genius, or as an ass.

~~~
malandrew
I suspect that I'd be marked as an ass, though I reckon I'd get brownie points
for correctively outing the bikeshedding.

In fact, it'd be even funnier to answer the question, then ask the question
"I'm building a bikeshed. What color do I paint it?"

------
terribleivan
Instead of asking me about golf balls and bus, would you not have
consideration for my intelligence and ask me a question that pertains to the
problems your company faces, and see me analyse it in various contexts,
leading to a richer interview? This way I will know something more about your
company and its work too, and you will know how I think about problems. In
your case, respect me enough to tell me your problem with number of clothes
and such and test me against it. Golfballs are Golfballs, your company's
problems are what I am hoping to solve. In that sense, you and your company
will earn my respect if you treat my time and insight as something valuable. I
will not solve golf ball problem for some myopic "insight" of questionable
value.

------
malandrew
If a company is solving interesting problems, I think that they won't even be
thinking about irrelevant problems for an interview.

Assuming a company has interesting problems that they are solving, why would
they willingly leave their interesting problems at the door instead of using
those problems as the basis for their interview dialogue.

The best interviews are a dialogue (not an interrogation!) where both the
interviewer and interviewee spend about equal time talking. Questions where
the interviewer spends a few seconds asking the question and the interviewee
spends several minutes answering is not demonstrative of real life
collaboration, and at the day the purpose of an interview is to recruit a
potential collaborator.

------
goldeneye
I don't see the problem with these questions. If you are really good it will
take you 5 minutes to answer that question. That is it. And lamenting about
interviewer waisting your time is ridiculous, you waist much more time every
day on the stuff that is less useful. The point of the question is to quickly
check if you can think logically that is it.

~~~
v0cab
It isn't a well-formed question. There's so many different kinds of buses,
there might be furniture, it might be toy bus, the doors might be open, it
might be an alien bus, it might be full with people or superglue; Who knows?
The question is so loosely-formed as to be nonsensical. You might as well ask
"How many/much object(s) can fit (insert spatial relationship here) (a/an/the)
thing(s)?"

~~~
goldeneye
Well to me it seems like a lot of questions in the real world are formed like
this. I.e. if you are asked to find how many customers will buy a book of your
website you make some reasonable assumptions like: The world will not come to
an end tomorrow You don't ask a person what should be defined as a book or
what should be defined as a buy etc. What I mean is that it is good to have
the ability to research the common case. And imagine the question about balls
was a real problem that your company faced, I don't think you would ask your
colleagues all the questions that you pointed out.

~~~
v0cab
But in this case (golf balls on a bus), I don't know what kind of assumptions
I can and cannot make. It isn't a real-world problem, so I can't use my
'common sense' to reason about its constraints.

------
rdg
I know why people keeps asking these questions: because it makes YOU look
smart. And also because it is/was a fad.

------
cnbeuiwx
How many idiotic interviewers does this company have?

At least 1.

------
georgieporgie
_Fermi problems come up all the time in computing_

Hm. I've never faced any such problem. But then, I do uninteresting stuff like
deciphering horribly documented APIs and writing desktop software.

If I go into an interview for a desktop software role and they start asking me
Fermi questions, I'm probably just going to walk out. In fact, if they ask me
questions that look like dynamic programming, I might walk out, too. Why?
Because I know they aren't _ever_ going to present me with such problems, and
they're just cargo-culting their interviews.

~~~
yummyfajitas
_If...they start asking me Fermi questions, I'm probably just going to walk
out...dynamic programming, I might walk out, too...I do uninteresting stuff
like deciphering horribly documented APIs and writing desktop software..._

Maybe if you stop walking out of tough interviews you'll find a more
challenging job.

~~~
georgieporgie
My last sentence explained why that's not an issue. If you're going to be
condescending, you should read more closely.

~~~
yummyfajitas
Yes, you believe they will never present you with such problems, even though I
gave two real life examples of where such problems come up.

~~~
georgieporgie
...real life examples which have absolutely nothing to do with any of the jobs
I've ever interviewed for. But hey, I'm sure you know about them better than
_I_ do.

Seriously, man, you need to get over yourself.

