
27 Jobs with Unbelievably Tough Interview Questions - sharjeelsayed
https://www.glassdoor.com/blog/jobs-with-tough-interview-questions/
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josephorjoe
I'm unbelievably tired of that hyperbolic headline writing style...

Some of those questions are perfectly reasonable for the roles. Some are just
annoying. It's the gotcha questions that I really can't stand.

> 14\. "How do you reverse a text string on the Unix command line?"

Meh... ruby -e "puts 'yourString'.reverse"

~~~
codingdave
This article is a thinly veiled ad for their own site. Clickbait title, starts
off with an implication that to prepare for interviews you should be reading
their site... oh, and then sure, they write an article, too. But everyone on
HN should be clever enough to see through this as little more than cheap
marketing.

~~~
josephorjoe
I know.

The sad thing is that I'm currently job hunting, I'm interested enough to give
a minute or two of my day to review some content of this type, I do use their
website to review companies, but then... they have to go and cheapen the whole
experience for both of us by coming on so hard.

Now, instead of being mildly intrigued by what they had to offer, I just feel
dirty for looking and want to go take a shower.

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davidwihl
The capital of Canada is an unbelievably tough interview question? Is Ottawa
that obscure or have we lowered our standards of geographical knowledge to
kindergarten level?

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denzil_correa
One of my favorite capital questions is "Capital of Australia". People
invariably end up with Melbourne. They are surprised when it turns out to be
Canberra - a city which in all likeliness they have never heard about.

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thirdsun
While I knew about Canberra, I always thought Sydney would be the most obvious
choice.

Brazil is another surprising one.

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ghaff
I'm guessing that Sydney is the only city in Australia that a lot of people
could name. (And Rio the only one in Brazil.)

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partycoder
"A hundred prisoners are each locked in a room with three pirates, one of whom
will walk the plank in the morning. Each prisoner has 10 bottles of wine, one
of which has been poisoned; and each pirate has 12 coins, one of which is
counterfeit and weighs either more or less than a genuine coin. In the room is
a single switch, which the prisoner may either leave as it is, or flip. Before
being led into the rooms, the prisoners are all made to wear either a red hat
or a blue hat; they can see all the other prisoners' hats, but not their own.
Meanwhile, a six-digit prime number of monkeys multiply until their digits
reverse, then all have to get across a river using a canoe that can hold at
most two monkeys at a time. But half the monkeys always lie and the other half
always tell the truth. Given that the Nth prisoner knows that one of the
monkeys doesn't know that a pirate doesn't know the product of two numbers
between 1 and 100 without knowing that the N+1th prisoner has flipped the
switch in his room or not after having determined which bottle of wine was
poisoned and what color his hat is, what is the solution to this puzzle?"

~~~
rogual
Always skip to the end when people post these to make sure you aren't wasting
your time.

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curiousgal
_> “What is the probability of an integer from 1 to 60,000 not having the
digit 6?”_

Am I missing something?

9 possibilities (0-9 excluding 6) for each of the last 4 digits and 6 (0-5)
for the first one.

6 * 9^4 = 39366

The probability is 100/39366 = 0.0025%

 _Edit:_ More perls; _" What is the angle at 3:15?"_ humm 0?

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akho_
Wrong answer to both questions. 0.0025 % of 60,000 numbers is 1.5. I can name
more numbers without a 6 than that; 1 and 2, for example. Other commenters
already wrote about the angle.

~~~
akho_
(Of course, the probability question is incomplete without a distribution; I
assume you were trying to solve for uniform)

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billpg
"12 hour clock or 24 hour clock?" "My clock has three hands. The angle of
which two hands?"

~~~
johan_larson
Hired!

~~~
nhumrich
Exactly, resolving ambiguity is the main thing I look for in interviews. It's
actually a very important skill. Business requirements are often ambiguous and
I need someone who can ask questions to make the more clear.

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anotheryou
Why do they ask about capitals? Relevant Feynman:
[https://youtu.be/ga_7j72CVlc](https://youtu.be/ga_7j72CVlc)

And nowadays we have google for some added prosthetic knowledge. It's becoming
increasingly important to grasp concepts well enough to ask the right
questions, but knowing simple unrelated facts by heart becomes irrelevant. At
most you have to remember that there was something to remember so you can look
it up.

edit: can a native speaker guide me on where to set commas correctly :) ?

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trapperkeeper79
The clock question always pissed me off in school. It assumes the clock's arms
move in a continuous way. The clocks I grew up with made discrete movements.

~~~
gnodar
It's an interview, not a test. Meaning you can, and should, ask questions back
for clarification.

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dudul
A few of these are reasonnable to see how someone is able to explain a concept
or make sense of something very anstract. Most of them though would make me
walk out the door in a heartbeat.

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mrlyc
> “Give me 48 cents using six coins. Tell me quantity and value of the six
> coins.”

That's easy. 2 x 20c and 4 x 2c.

Nobody said the coins had to be American and still in circulation.

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DannyBee
It's not hard anyway?

It seems like it would take about a minute to work it out.

1x25c 2x10c 3x1c

It's pretty nearly the first thing you'd probably try. (2 quarters can't work,
so it must be 1 or zero, let's assume one, 23 cents left, 3 dimes can't work,
let's assume 2, 3 cents left, no nickels can work, 3 pennies, done)

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anpcre
One more tricky one that I was asked upon : When is the only case that 2+2=5 ?

Any answers ???

Ofcourse the answer baffled me

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tzs
> 4\. “Who in history would you want to go to dinner with and why?”—Flight
> Attendant, PSA Airlines

I was asked a similar question, but in a quite different context. I was on
jury duty in the Los Angeles area in July, 1987. Our panel was sent to a
courtroom that needed a jury for some drug charge. The procedure was that 14
from the panel would sit in the jury box (12 jurors plus 2 alternates), where
we'd be questioned by the judge and lawyers, and if any of us were rejected
for that jury, someone else from the panel would take their place and be
question. Repeat until there are 12 acceptable jurors.

One of the questions the defense attorney asked us was if we could have dinner
that night with anyone in the world, living or past, who would we choose? I
was in the fifth seat in the front row, so had some time to think before he
got to me. The answers ahead of me were the candidate's deceased mother,
Richard Feynman, Pope John Paul II [1], and I forget the other.

Then he asked me.

I said "Adolph Hitler".

A lot of the panel that was not in the box (maybe 30 people) had been kind of
nodding off, as this was boring, and the courtroom was hot (it was the middle
of summer, and the courtroom was not air conditioned). My answer woke them all
up.

The attorney asked why and I explained that Hitler did terrible things to
other people, and was clearly insane. That makes him at least interesting, but
not unique. What sets Hitler apart, and makes him a good candidate for dinner,
is that he somehow got a lot of apparently sane, rational, educated, well-off
people to willingly help him commit his atrocities. He must have had
tremendous charisma or something in order to get those results, and so a
dinner with him should be very interesting.

The prosecutor also asked us a far out question. She asked us what we would
say if aliens (the space kind, not the human from another country kind...)
contacted us and said they had been monitoring our news and were confused
about the "drug problem", and asked us to explain it.

I told her that I would tell them that we have arbitrarily classified some
drugs as illegal and some as legal, without much regard to the actual harm of
each, and so we have some drugs legal (alcohol, tobacco...yes, I know these
might not scientifically be drugs, but for purposes of drug law policy they
are effectively drugs), and some illegal (marijuana, LSD, cocaine, heroin, for
instance), even though some of the latter group (such as marijuana) do the
same or less harm than some in the former group. Then on top of that we don't
admit that this is arbitrary and irrational, and so our schools, police, and
government lie to kids telling them that drugs like marijuana are as bad as
heroin. Of course, the kids end up trying marijuana, find out that they were
lied to, and then do not trust the advice they've received on other drugs, and
so likely end up trying drugs that really ARE bad. And then we waste a lot of
money trying to enforce these stupid laws on things like marijuana when we
could be putting that money and time toward real problems. She tried to defend
the drug laws and policy, and we argued for a bit before she moved on.

So...basically...I told the prosecutor that this case was stupid and
irrational, and she is working for a system that purposefully lies and makes
the problems worse. Oh, and I had long hair and a beard and was wearing a tie-
dye shirt that made me look like a hippy who had just come from a Grateful
Dead concert and was probably on drugs right now.

I was pretty sure at this point that I was not going to make it onto that
jury. The only question was whether it would be the defense or the prosecution
that used one of their three peremptory challenges to kick me off.

I was guessing it would be the prosecutor, because I had basically told her I
considered this whole thing stupid and harmful. On the other hand, I did say
when asked that I would vote according to what the law says, regardless of how
stupid I thought that law or its application was, and they knew I was a
software engineer with a math degree from Caltech and so might have felt that
this made it believable that I would be able to let logic rule instead of
emotion.

It was actually the defense that did it. The prosecutor used all 3 of hers on
other people, and the defense used his first 2 on others, then took me out
with his final one. I think they were both holding off because they each
thought the other might take me out.

[1] This was in July, 1987, so John Paul II was the current Pope, and Feynman
was still alive.

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dudul
Capital of canada? Is that considered unbelievably tough now?

~~~
overcast
Most people think the capital of New York is New York. Ottawa isn't exactly on
anyone's world destination list. Completely reasonable that the majority of
people wouldn't know that.

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dudul
OK, I guess I underestimated how basic this information was. Now, I'm
wondering what the interviewer is trying to prove by asking this question.

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samfisher83
Wouldn't the angle at 3.15 be so 0 or 2pi*n

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tzs
> “Prove that hoop stress is twice the longitudinal stress in a cylindrical
> pressure vessel.”—Test Operations Engineer, SpaceX

Well, I have no idea whatsoever how to approach that...but I would not be
applying to be a test engineer at a rocket company. This sounds like something
that an actual rocket engineer should know, and I would guess that it is even
something that would be easy for such an engineer.

> “What is the first thing you’d print with a 3D printer if you had
> one?”—Linux Systems Administrator I, Rackspace

I'd print whatever test object the printer's instructions say to print to
verify that I have set the printer up correctly and that it is working.

> “Please describe an instance where you had to make a decision without all of
> the necessary information.”—Analytics, athenahealth

The obvious answer is "this interview".

> 27\. “How would you find the square root of 1.2?” —Hardware Engineer, Jump
> Trading

I would guess that some context is missing here. I don't think it means that
if you needed the square root of 1.2 for something you were doing, how would
you obtain it. I expect it is asking how you would do it in hardware, or in
firmware. It's then time to talk about what computational ability the hardware
has. For example, if it is going to be firmware, is there a divide instruction
on the processor? Do we have floating point or are we using fixed point? How
accurate does it need to be? Yadda yadda.

If it _is_ asking how you would obtain it for yourself, then the correct
answer is use a calculator, unless you just need a quick approximation, in
which case it is to note that 11^2 = 121, so 1.1^2 = 1.21, and so 1.1 is a
pretty good approximation to sqrt(1.2). If you need slightly better, but still
cannot use a calculator, note that 1.1 is slightly high, and assume the right
answer is 1.1-x. That gives (1.1-x)^2 = 1.2, which can be rewritten as x =
0.01/(2.2-x). If x is small, we can neglect it in 2.2-x, suggesting we look at
x = 0.01/2.2. Let's approximate 2.2 with 2 to make the mental math easier,
giving us x = 0.005. That gives us a new approximation for sqrt(1.2) of 1.1 -
0.005 = 1.095. That is quite close. It's square is 1.199025.

If you want an answer that works well under both the "it's for firmware"
interpretation and the "it's for me and I don't have a calculator"
interpretation is to use the binomial theorem. For square roots, that says
sqrt(1+x) = 1 + x/2 - x^2/8 + x^3/16 - 5x^4/128 + ...

With x = 0.2, that's 1 + 0.1 - 0.005 + 0.0005 - ... Note that if you stop at 3
terms you get the same approximation I got earlier, 1.095. Four terms gives
1.0955. That's a good place to stop because 5 terms gets harder to do mentally
because of that stupid 5/128.

~~~
ghaff
I believe the hoop stress vs. longitudinal stress question is approximately
true specifically for thin-walled pressure vessels. However, it is many many
years since I would have been able to prove that--probably about the time I
took the final exam in that particular course :-)

Especially given modern computer tools, I'm actually not sure how many
mechanical engineers would be able to derive that sort of thing in an
interview. I wouldn't have been able to but you probably didn't want me
designing rockets either.

