Chapter 11: Paul & Dominic’s Guide to Getting a Quant Job 409
- Off the wall.Example: How many manhole covers are
there within the M25?
Work through the Brainteaser Forum onwilmott.com.You
can practice for IQ tests, and the more you do, the better
your score. Brainteasers are no different. And you’d be
surprised how often the same questions crop up.
It’s worth having a few numbers at your fingertips for
the ‘‘manhole covers.’’ One manager recently told us
in rather despairing tones of the stream of candidates
who didn’t have even a rough approximation to the
population of the country they were born and educated
in. Several put the population of Britain between 3 and
5 million (it’s around 60 million). A good trick when
‘‘estimating’’ is to pick numbers with which it is easy to
do mental arithmetic. Sure you can multiply by 57, but
why expose yourself to silly arithmetic errors.
In many types of question, they want to hear your
train of thought, and have simply no interest in the
actual answer. Thus you need to share your thoughts
about how you get to each stage. You also should ‘‘san-
ity check’’ your answers at each step, and make sure
they’re aware you’re doing it. This is a soft skill that’s
very important in financial markets where the money
numbers you are manipulating are rather larger than
your credit card bill.
At entry level we also see people being asked what we
call ‘‘teenage maths.’’ You’ve probably been focusing
on one area of maths for some years now, and to get
this far you’ve probably been good at it. However some
banks will ask you to do things like prove Pythagoras’
theorem, calculateπto a few decimal places, or prove
that the sum ofNnumbers isN(N+1)/2. That last fact
being surprisingly useful in brainteasers.
