From The Sunday Times
November 8, 2009
Here’s a tricky one, Google
The cyber giant fires tough and quirky questions at job applicants. We ask why
Roland White
Imagine yourself at the head of a desperate band of pirate cut-throats. For some readers
— investment bankers, members of parliament — this should not be too difficult. You’ve
enjoyed a very good financial year bringing terror to the high seas and now is the time to
divvy up the loot. From a management point of view, there is just one snag. If the crew
don’t like the size of their bonuses, they will run you through with their cutlasses and
possibly introduce woodworm into your false leg. What do you do to ensure you get the
biggest share of the treasure, but live to enjoy it?
You might be surprised to learn that this is just the sort of situation you could face while
working for Google, the world’s cyber superpower. Clearly, life at the cutting edge of
search-engine development is rather tougher than we’ve been led to believe. The question
is just one of the problems that job applicants are expected to solve at interviews off the
tops of their heads (no Googling allowed, obviously).
If you also know, say, how to get four people across a rickety bridge under difficult
circumstances at night — flashlight that will last only 17 minutes, bridge can’t hold more
than two people, one of the party takes half an hour to cross but needs to go to the
lavatory halfway, the usual stuff — then all the better.
These days interviews are rigorous, and if you’re trying to get a job with Google they don’t
come much tougher. The company, which employs about 20,000 people worldwide, gets
3,000 job applications a day. Just to give you some idea of the competition for jobs, there
were only 50 UK vacancies being advertised last week.
An extensive list of Google questions was posted last month on a blog written by Lewis
Lin, a recruitment consultant in Seattle who has helped young graduates to find jobs with
both Google and Microsoft. Many are software and engineering problems that you might
expect to be asked at an interview for a big computer firm. But you can also expect to be
asked about those pirates, 100 adulterous husbands, manhole covers and all the dirty
windows in Seattle.
How times have changed. It’s not that long ago — probably about 20-30 years — when job
interviews at big companies went something like this:
Interviewer: “Didn’t your father used to work here?”
Interviewee: “Yes. He sends his best wishes.”
Interviewer: “Do you still play rugby, by the way?”
Interviewee: “Yes.”
Interviewer: “Jolly good. When can you start?”
This was the way young people got jobs pretty much everywhere. Not any more.
According to computer geek legend, it was Microsoft that first started using puzzles in
formal job interviews, largely because Bill Gates enjoyed puzzles more than he enjoyed
interviewing. But such questions will be familiar to university applicants, who’ve had to put
up with this sort of thing for years.
A book called So You Want to Go to Oxbridge? Tell Me About a Banana lists the sort of
questions that Oxford and Cambridge applicants have faced in recent years. “If ancient
history has a shape, what shape might that be?” is one of them. “What is the most
interesting thing about a squirrel?” is another (to which the answer is, duh, obviously: “red
squirrel or grey squirrel?”).
“Microsoft and Google are known as the two companies that have historically used brain
teasers in the interview process,” says Lin. “Candidates usually react in one of two ways.
Some dismiss puzzle or estimation questions as ridiculous; others clam up under the
stress of an unfamiliar question. As far-fetched as the question may sound, do take it
seriously. Take a deep breath, give it your best shot.”
Some questions don’t actually have an answer. The interviewer is looking for an analytical
approach rather than a correct solution. And even if you get the job, you won’t necessarily
discover the right answer to the questions.
“Many of us here are still trying to figure out how many tennis balls can fit into a small
room, or the number of people currently travelling by air in the world,” says Laura Scott,
Google’s UK spokeswoman.
“Googlers love creative ideas, finding innovative solutions and cracking complex problems
— it’s what keeps us on our toes. That’s why we aim to ask many different and engaging
questions in interviews.
“The questions give us a sense of how someone works through a difficult problem, which
in turn helps us get to know a person and see whether they would be a good fit for
Google.”
Sometimes — just sometimes — interview questions are easier than they seem. When
Professor Marcus du Sautoy was interviewed to read maths at Oxford, he was asked
whether he could change a light bulb. “I thought I was meant to come up with a witty joke,”
says du Sautoy, now Oxford’s professor for the public understanding of science. Actually,
the tutor just wanted some help to change his light bulb.
Figure these out
Are you the right stuff for Google? Here are nine typical questions asked at Google
interviews. Answers have been supplied by Marcus du Sautoy, Oxford University professor
for the public understanding of science; Alexander Paseau, philosophy fellow at Wadham
College, Oxford; David Wallace, philosophy of physics fellow at Balliol College, Oxford;
Roland White, professor for the private misunderstanding of science at the University of
Wapping.
1 You have eight balls all of the same size. Seven of them weigh the same. One of them
weighs slightly more. How can you find the heavier ball by using a balance and only two
weighings?
2 You’re a pirate ship captain, and your crew gets to vote on how the gold is divided. If
fewer than half the pirates agree with you, you die. How do you recommend apportioning
the gold in such a way that you get a good share of the booty, but still survive?
3 Every man in a village of 100 married couples has cheated on his wife. Every wife in the
village instantly knows when a man other than her husband has cheated, but does not
know when her own husband has. The village has a law that does not allow for adultery.
Any wife who can prove that her husband is unfaithful must kill him that very day. The
women of the village would never disobey this law. One day, the queen of the village visits
and announces that at least one husband has been unfaithful. What happens?
4 How many golf balls can fit in a school bus?
5 How much should you charge to wash all the windows in Seattle?
6 How many times a day do a clock’s hands overlap?
7 How many piano tuners are there in the world?
8 Why are manhole covers round?
9 A man pushed his car to the hotel and lost his fortune. What happened?
Answers
1 Weigh balls 1, 2, 3 against 4, 5, 6. If they balance, compare 7 and 8; if they differ, take
the heavier set (say 1,2,3) and weigh 1 and 2. If they balance, ball 3 is heaviest.
2 If there are N pirates, give half of them just over 1/N of the loot each (which is more than
they’d expect by even distribution). Keep the remaining loot (just under half the total).
3 Suppose there are only two married couples in the village. When the queen makes her
announcement, Wife 1 knows Husband 2 was unfaithful. Now she knows that if Wife 2
sees that Husband 1 is faithful then Wife 2 will kill Husband 2 on the first day because at
least one of the two men is unfaithful and it isn’t Husband 1. However, Wife 2 doesn’t kill
her husband. The only reason being because she knows Husband 1 is unfaithful. Because
both husbands are still alive on the second day the wives know both are unfaithful. So on
the second day both husbands are killed by their wives. What happens with 100 married
couples is that the wives have to wait till the 100th day before they can prove that their
husband is cheating. On the 100th day there is a bloodbath: all the men are killed by their
wives.
4 Full marks for mentioning the Kepler conjecture on packing spheres into a threedimensional space. The fraction of the volume you can fill is /(3 2). “This comes out at
roughly 74%”, says Professor du Sautoy.
5 We got a quote: Valhalla window cleaning service of Seattle says it will do all the
residential windows for $90m and all the commercial ones for $100m. Valhalla usually
charges $125 for a “normal” 18-window house.
6 22 7 The UK’s Pianoforte Tuners’ Association has 200 members, but vice-president
John Lambert thinks there are about 1,000 people tuning British pianos. Let’s say the UK
population is 60m. That’s one tuner per 60,000 of the population. Let’s then make the
assumption that everybody in the world — approx 6.7 billion — is as keen on playing the
piano as the British (and yes, it’s a rather unlikely assumption). That means there are
111,667 piano tuners in the world. But Dr Wallace puts the figure at 10,000. “There aren’t
many outside the West’s 600m population,” he says. “The average town has maybe two or
three but is servicing a wider area with maybe another 50,000 people. So, vaguely, one
per 50,000. Or about 10,000.”
8 They’re not always round, but you can’t drop a round cover down the hole like you can
with a square cover (which can fall down the diagonal). “The shape of a 50p coin will also
work,” says Professor du Sautoy.
9 He was playing Monopoly.
Additonal reporting Josh Glancy
Copyright 2009 Times Newspapers Ltd.