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The Key to Nailing Any Brainteaser at Your Next Interview

Updated: Feb 7

“How many dollar bills are in Chicago?”

For many job applicants, you may not know where or how to start your answer. It can even seem tempting to blurt out that you have no clue. These questions are known as brainteaser questions, and they’re commonly asked by tech companies. However, there’s no reason to break a sweat when an interviewer poses this question. And here’s why.


Brainteasers are easy to identify during an interview. They are often phrased as a puzzle or problem that requires critical thinking. Typically, you won’t have any experience with solving the question, so you must rely on making several assumptions to reach your final answer.

While these questions do require problem-solving skills, brainteasers should not be confused with technical questions. Technical questions are those that are directly related to the position and require an understanding of tech-related concepts. Employers use technical questions to assess whether candidates have the requisite knowledge that meets the requirements for the job. Brainteasers, however, are not directly related to the position. Instead, employers use these questions to assess whether the applicant’s soft skills, such as creativity and analytical skills, can help the applicant succeed on the job.


There are two common types of brainteasers: the “how many..” and riddle questions.

“How many…”

The “how many…” question refers to brainteasers where the applicant must estimate a statistic. For example, interviewers can ask you how many taxi drivers are in New York City, or how many whole pizzas a person eats in their lifetime. When answering these questions, the key thing to note is that there is no right or wrong answer. The interviewer is only evaluating how you think through the problem and achieve your answer. Therefore, narrate your decision making out loud and be confident with your assumptions.

Let’s return to the question asked in the beginning: “How many dollar bills are in Chicago?” This is a “how many... “ question type. To start off your answer, tell the interviewer some key assumptions. This can include how many dollar bills people keep in their wallet and at home, how many people are in Chicago, how many dollar bills are at a bank, and how many banks are in Chicago. The “how many..” questions can always be broken down and rebuilt to formulate your answer, and that is exactly what the interviewer is looking for.


Riddle questions range in all subjects. It can be anything from why manhole covers are round to how you can move Mount Everest. Similarly to “how many…” questions, there are no correct answers. If you are confused, ask specific clarifying questions to the interviewer. Then, break down the question and narrate your thoughts out loud. Most importantly with riddle questions, the interviewer wants to see creativity and confidence, so make sure you stand your ground and back up all assumptions with a logical answer.


Now that you have an idea of what brainteasers you can see at your next interview, you may not know why these questions are asked. Employers are interested in your problem-solving skills, analytical abilities, creativity, and ability to quickly think on your feet.

For example, even if you make incorrect assumptions, the interviewer will still observe your thought process. Employers want to know what type of thinker you are and whether that fits into the company’s work culture. Remember, there are often no right answers to brainteaser questions. Therefore, stick with your thought process and be confident in your assumptions.


While there are many types of brainteasers, there are four main steps to ace any question thrown your way.

1. Ask for clarification

The most important step is understanding what the question is asking for. If you are unsure of this, it’s vital that you ask questions before you start calculating your answer. Treat the brainteaser question as a conversation between you and the interviewer, so don’t hesitate to toss a question back at the interviewer. This step can also buy you extra time to determine a strong, logical thought process before saying it out loud.

2. Break down the question into manageable chunks

Every brainteaser can be broken down into individual parts. It’s safe to think that you can assume some of the individual components, such as how many dollar bills a person carries in their wallet. However, it’s not safe to assume how many dollar bills a person owns, as a typical person will have dollar bills in their wallet and in their home. Break it down as much as possible. Then make your assumptions.

3. Calculate your answer out loud

After stating your assumptions to the interviewer, you should continue to narrate the calculations you make. This can help the interviewer pinpoint where you went right or wrong. If you went wrong, the interviewer may interrupt you and allow you to retry your calculations. But, if you didn’t say your calculations out loud, you risk the chance of not having a second opportunity.

4. Justify your decision-making process

The last step is explaining why your decision-making process is valid, as well as clearly stating your answer. The interviewer cares more about your thought process than your answer. Therefore, make sure you can back up your assumptions, logic, and calculations. Now, you’re done!


It’s hard to predict the types of brainteasers you will be asked at your next interview. However, similarly to behavioral interviewing, practice is key. Here are 10 common brainteasers employers use:

1. How many pennies are in New York City?

2. How many gas stations are in the United States?

3. How many trees are in New York City’s Central Park?

4. Why are manhole covers round?

5. Describe the color purple to a blind person.

6. Why is a tennis ball fuzzy?

7. You have a one gallon jug and a three gallon jug. How do you measure out exactly two gallons?

8. How many gallons of water do you drink in a year?

9. How many chocolate cakes are sold in New York City bakeries each year?

10. How many ping pong balls can fit in a Boeing 747?


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