Are brainteasers still popular?

I've read that a bunch of the EB's that I hope to interview with tend to ask some brainteasers during interviews. However, most of the brainteaser threads on WSO are from 2009-2013ish and they don't seem to pop up too much nowadays, especially at larger banks.

Do you think I should still prep/worry about them, especially for EB's?
Has anyone had any recent experience with those types of questions?
Any general advice/ strategies / approaches on how to go about solving them during an interview?

 

100%, at EBs especially. Did a superday at Centerview Partners last year, and 2 out of 5 of the 30-minute interviews were brainteasers/weird fit questions. Things like: estimate how many bricks are on your college campus, what song best describes your work style, name 10 uses of a pencil besides writing. All interviewers were given a sheet with a pool of pre-approved questions that they chose from. They change every recruiting season.

Look through the WSO company database as well as Glassdoor. Some of these questions you can't really prepare for, but having a fun and positive attitude and not looking nervous as fuck really does help, I think.

 
Best Response

It is really going to depend on the interviewer and to be honest the universe of questions is so vast that I wouldn't spend a ton of your prep time going over these. At least have a general sense of how you would answer a few of the ones mentioned above. Otherwise focus on technical questions, your story, your rationale for joining that X bank, knowing the details of an M&A deal or two, having a stock or two that you follow/could pitch.

What I would also prepare for is mental math questions which I've gotten a number of at EB's especially. Something like 23x23 in your head is going to throw most people off if you're not ready, but is actually pretty doable if you break it down:

3x3 = 9 20x3 = 60 20x3 = 60 20x20 = 400

9+60+60+400 = 529

Also know your fractions: 1/2 = .50 1/3 = .33 1/4 = .25 1/5 = .20 1/6 = .16 etc.

A very popular question is something like, imagine a company is buying another company with a P/E of 14.0 - what is the cost of debt that would lead to an accretive deal?

First clarify if that is after-tax cost of debt (they say yes) and basically it is the inverse of 1/14. You know 1/7 is ~0.14, so 1/14 is approximately 0.07 so the cost of debt would have to be less than 7%

 

Brain Teasers with Definitive Answers

What is the angle between the hands on the clock if the time is 3:15?

You have a block of cheese painted all red only on the outside. If you cut the block into 10 by 10 squares, how many squares will have red paint on any portion?

You have 12 black socks and 18 white socks in a drawer. The power goes out in your house and you can't see anything. How many socks do you need to pull out of the drawer to make sure that you have at least one matching pair of either color?

You have a 5 gallon bucket and a 3 gallon bucket. You need to make a container with exactly 4 gallons of water in it, how is this possible?

What is 23^2?

What is 17*23?

A driver is going to drive 100 miles. If they drive the first 50 miles at 50 miles per hour, how fast do they have to drive the second to average 100 miles per hour for the entire run?

A stock is trading at 10 and 1/16. There are 1 million shares outstanding. What is the stock’s Market Cap?

You are the owner of a large mid-evil farm and your peasants demand that they are paid every day in bars of gold. You have a measuring device that allows you to cut the bar of gold in exactly the length that you please. Your peasants work 7 days a week. You can only cut the gold bar twice. How can you pay your peasants?

Three missionaries and three cannibals want to get to the other side of a river. There is a small boat, which can fit only two. To prevent a tragedy, there can never be more cannibals than missionaries together. How is this possible?

There are three switches downstairs. Each corresponds to one of the three light bulbs in the attic. You can turn the switches on and off and leave them in any position. How would you identify which switch corresponds to which light bulb, if you are only allowed one trip upstairs?

A Petri dish hosts a healthy colony of bacteria. Once a minute every bacterium divides into two. The colony was founded by a single cell at noon. At exactly 12:43 (43 minutes later) the Petri dish was half full. At what time will the dish be full?

There are ten apples in one basket and ten people in a room. Can you distribute the apples so that each person received one and there is one apple left in the basket? A professional fisherman caught 30 fish during a 5-day tournament. Each day, he caught three more fish than the day before. How many fish did the fisherman catch on the first day?

Find the four-digit number in which the first digit is one fourth of the last digit, the second digit is 6 times the first digit, and the third digit is the second digit plus 3?

A man wanted to enter an exclusive club but did not know the password that was required. He waited by the door and listened. A club member knocked on the door and the doorman said, "Twelve." The member replied, "Six" and was let in. A second member came to the door and the doorman said, "Six." The member replied, "Three" and was let in. The man thought he had heard enough and walked up to the door. The doorman said, “Ten" and the man replied, "five." But he was not let in. What should have he said?

Does the Catholic Church allow a man to marry his widow's sister?

Brain Teasers without Definitive Answers (5) How tall is the Empire State Building in terms of quarters stacked on their sides?

How many ping-pong balls fit into a 787 Dreamliner?

What is the annual snowfall over the United States in inches?

One stock is trading at $8 and another is trading at $34, which one has the higher growth potential?

How do you explain the sky to a blind person?

 
FinancelsWacc:
Brain Teasers with Definitive Answers

What is the angle between the hands on the clock if the time is 3:15?

You have a block of cheese painted all red only on the outside. If you cut the block into 10 by 10 squares, how many squares will have red paint on any portion?

You have 12 black socks and 18 white socks in a drawer. The power goes out in your house and you can't see anything. How many socks do you need to pull out of the drawer to make sure that you have at least one matching pair of either color?

You have a 5 gallon bucket and a 3 gallon bucket. You need to make a container with exactly 4 gallons of water in it, how is this possible?

What is 23^2?

What is 17*23?

A driver is going to drive 100 miles. If they drive the first 50 miles at 50 miles per hour, how fast do they have to drive the second to average 100 miles per hour for the entire run?

A stock is trading at 10 and 1/16. There are 1 million shares outstanding. What is the stock’s Market Cap?

You are the owner of a large mid-evil farm and your peasants demand that they are paid every day in bars of gold. You have a measuring device that allows you to cut the bar of gold in exactly the length that you please. Your peasants work 7 days a week. You can only cut the gold bar twice. How can you pay your peasants?

Three missionaries and three cannibals want to get to the other side of a river. There is a small boat, which can fit only two. To prevent a tragedy, there can never be more cannibals than missionaries together. How is this possible?

There are three switches downstairs. Each corresponds to one of the three light bulbs in the attic. You can turn the switches on and off and leave them in any position. How would you identify which switch corresponds to which light bulb, if you are only allowed one trip upstairs?

A Petri dish hosts a healthy colony of bacteria. Once a minute every bacterium divides into two. The colony was founded by a single cell at noon. At exactly 12:43 (43 minutes later) the Petri dish was half full. At what time will the dish be full?

There are ten apples in one basket and ten people in a room. Can you distribute the apples so that each person received one and there is one apple left in the basket? A professional fisherman caught 30 fish during a 5-day tournament. Each day, he caught three more fish than the day before. How many fish did the fisherman catch on the first day?

Find the four-digit number in which the first digit is one fourth of the last digit, the second digit is 6 times the first digit, and the third digit is the second digit plus 3?

A man wanted to enter an exclusive club but did not know the password that was required. He waited by the door and listened. A club member knocked on the door and the doorman said, "Twelve." The member replied, "Six" and was let in. A second member came to the door and the doorman said, "Six." The member replied, "Three" and was let in. The man thought he had heard enough and walked up to the door. The doorman said, “Ten" and the man replied, "five." But he was not let in. What should have he said?

Does the Catholic Church allow a man to marry his widow's sister?

Brain Teasers without Definitive Answers (5) How tall is the Empire State Building in terms of quarters stacked on their sides?

How many ping-pong balls fit into a 787 Dreamliner?

What is the annual snowfall over the United States in inches?

One stock is trading at $8 and another is trading at $34, which one has the higher growth potential?

How do you explain the sky to a blind person?

These are great. However, I think this might actually be a test for attention to detail because of this:

“a large mid-evil farm”

mid-evil??? I don’t think that’s an autocorrect mishap. It’s a test within a test.

 

Most of the stuff mentioned in this thread is such nonsense. Nothing to do with performing the job well, and just a lazy way for interviewers to weed out a mass of kids

The only potentially relevant ones are off the wall stuff that shows what kind of person someone is and how they can present themselves (song to describe work style) or questions actually relevant to the job (which company has more growth potential)

10 other uses for a pencil? I can only think of one... stabbing myself in the eye with it so I can escape from such a bizarre waste of time

 
BDWK:
Agree that a lot of them are laughable. Very hard to prepare for those odd-ass questions so it's just a way for interviewers to induce pressure and see how you react. Maybe they're even looking for a little creativity in your answer? As the interviewee, it's hard to take some of them seriously, though. "You're shrunk down to the size of a pencil and put in a blender, how do you get out?"

WTF? It would be pretty difficult to answer that question with a straight face.

Honestly if someone asked me that now in an interview, I’d just walk out. Wouldn’t want to work for someone that thinks that is an effective way to conduct an interview. Granted I’m past the point where I’d be applying for an entry level job, but such a question provides no relevant information

 
BDWK:
Interesting point. Perhaps this is strictly an entry-level or intern kind of question? I believe the blender question was asked at Goldman for their summer internship.

I think so. It is just a random hoop that interviewers make kids jump through because there are so many applicants

When I interview someone, here are some of the things I personally look for:

1) Does this person have enough relevant subject knowledge and skills to add value quickly in the job and efficiently learn as required. They don’t need to know everything, nor should they

2) Is this person results driven and comfortable with taking ownership of a project

3) What drives this person, what makes them tick and come alive. What are their goals and dreams

4) What kind of person are they. What are their past experiences like which colors their perspective of the world

5) Do I like this person. Do they have a sense of humor, outside interests, operate on a similar frequency

Notice that pencil figure in a blender or ping pong balls in an airplane helps me answer precisely none of these questions

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