
What interview questions did D. E. Shaw ask Larry Summers? - gabrielroth
http://www.slate.com/id/2215503/
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tokenadult
Cool. A press interview with Richard Rusczyk about his work before he founded
the Art of Problem Solving website.

<http://www.artofproblemsolving.com/Forum/index.php>

Rusczyk always has something interesting to say.

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chris11
Yeah, I found the site when I was looking for material to study for the
Putnam. It is a great site for learning about advanced math topics and even
finding more challenging pre-college math material, by the way.

I got the impression that he was really brilliant. Here's his
blog:<http://www.artofproblemsolving.com/Forum/weblog.php?w=1>

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tomsaffell
[Warning: Spoiler]

> _Of course, you can't offer the guy infinity dollars. So the interviewee is
> forced to either settle on a real world number—as much as the player can
> afford—or delve into marginal utility theory_

I don't think that _as much as the player can afford_ is a real world answer,
unless it means _as much as the player can afford to lose_. There is a 50%
chance he'll walk away with $1. As Wall Street have proven, it's not about
maximizing expected returns, it's about optimizing returns within bounds of
acceptable risk.

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aristus
It bugged me too, but hey, that's journalism.

My gut said 3 bucks. That's about as much as I would want to lose on a
Martingale bet.

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trjordan
But you're playing the house to his Martingale bet, right? If the game was
repeated, you should be willing to bet all your money on it, since the odds
are in your favor.

I think the question checks your ability to understand the mathematical
potential payoff, but also to weigh that against the real-world consideration
of risk.

~~~
aristus
I suppose. But there's a difference between "mathematical potential payoff"
and how much I will risk on the flip of a coin. And as far as I can tell, the
amount I pay has no effect on the odds or rules. So, three bucks.

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trjordan
Oh, absolutely, and that's the point of the question. My guess is that the
answer "three bucks" and the answer "Well, the expected payoff is infinite,
but ... three bucks" is the difference between the door and an offer.

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aswanson
I've never done a trade in my life and it took all of about 12 seconds to get
the right answers on the first two. They didn't list the third. Seriously, 5.4
MM for
that?...[http://www.bloomberg.com/apps/news?pid=20601087&sid=a4iG...](http://www.bloomberg.com/apps/news?pid=20601087&sid=a4iGjejJVRko&refer=home)

~~~
chris11
Here's a forum with the type of questions that more likely to be asked. These
questions are more difficult.
<http://www.wilmott.com/categories.cfm?catid=26>:

Example brainteaser:

"Last night I sat behind two wizards on a bus, and overheard the following:

A: I have a positive integral number of children, whose ages are positive
integers, the sum of which is the number of this bus, while the product is my
own age. B: How interesting! Perhaps if you told me your age and the number of
your children, I could work out their individual ages? A: No. B: Aha! AT LAST
I know how old you are!

Now what was the number of the bus?"

Discussion:
[http://www.wilmott.com/messageview.cfm?catid=26&threadid...](http://www.wilmott.com/messageview.cfm?catid=26&threadid=68570)

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jibiki
Wow, I read through the discussion. No way in hell anyone would be able to
answer that in an interview, unless they'd seen it before.

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shrughes
It's definitely answerable in an interview situation. Some people should be
able to answer it, no problemo, in a minute or two.

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jibiki
I don't think you understand the problem. Even if you manage to find 4, 4, 3,
1 and 6, 2, 2, 2, you still have to verify that if the sum is 12, then there
is only 1 possible product. You'll note that nobody in the linked thread
succeeds at this (one guy proves that 12 works by exhaustive search, not
really a possibility in an interview...)

~~~
shrughes
Well, I saw it before, and it took a several minutes then, maybe 5 or 15, I
don't really remember. Then you have to consider that companies like D.E. Shaw
end up hiring people who would end up giggling at how long somebody slow like
me would take to solve the problem.

