Interview Questions: Finance Interview
Brainteasers by Vault
Perhaps even more so than tough finance questions, brainteasers can unnerve the most icy-
veined, well-prepared finance candidate. Even if you know the relationships between
inflation, bond prices and interest rates like the back of a dollar bill, all your studying may not
help you when your interviewer asks you how many ping pong balls fit in a 747.
That is partly their purpose. Investment bankers and other finance professionals need to be
able to work well under pressure, so many interviewers believe that throwing a brainteaser at
a candidate is a good way to test an applicant's battle-worthiness. But these questions serve
another purpose, too - interviewers want you to showcase your ability to analyze a situation,
and to form conclusions about this situation. It is not usually important that you come up with
a "correct" answer, just that you display strong analytical ability.
Remember, brainteasers are very unstructured, so it is tough to suggest a step-by-step
methodology. There are a couple of set rules, though. First, take notes as your interviewer
gives you a brainteaser, especially if it's heavy on the math. Second, think aloud so your
interviewer can hear your thought process. Here are some samples:
If you look at a clock and the time is 3:15, what is the angle between the hour and the
The answer to this is not zero! The hour hand, remember, moves as well. The hour hand
moves a quarter of the way between three and four, so it moves a quarter of a twelfth (1/48)
of 360 degrees. So the answer is seven and a half degrees, to be exact.
You have a five-gallon jug and a three-gallon jug. You must obtain exactly four gallons of
water. How will you do it?
You should find this brainteaser fairly simple. If you were to think out loud, you might begin
by examining the ways in which combinations of five and three can come up to be four. For
example: (5 - 3) + (5 - 3) = 4. This path does not actually lead to the right answer, but it is a
fruitful way to begin thinking about the question. Here's the solution: fill the three-gallon jug
with water and pour it into the five-gallon jug. Repeat. Because you can only put two more
gallons into the five-gallon jug, one gallon will be left over in the three-gallon jug. Empty out
the five-gallon jug and pour in the one gallon. Now just fill the three-gallon jug again and pour
it into the five-gallon jug. Ta-da. (Mathematically, this can be represented 3 + 3 - 5 + 3 = 4)
You are faced with two doors. One door leads to your job offer (that's the one you want!),
and the other leads to the exit. In front of each door is a guard. One guard always tells the
truth. The other always lies. You can ask one question to decide which door is the correct
one. What will you ask?
The way to logically attack this question is to ask how you can construct a question that