Why companies ask tough "brain teaser" questions - and how you should answer them

Charlie Benson
Content Marketing Executive

Standard interview questions about yourself and your career aspirations are nerve-wracking as it is, but some companies like to ask pretty out-there, curveball questions to test candidates further.

These awkward interview questions are hard to prepare for, because they’re designed to challenge you with something you aren’t expecting to test how you think on your feet, not how well you can rehearse responses to the usual questions.

If you’re confronted with an offbeat question in an interview, the key is not to panic or to appear flustered when presented with something you don’t immediately know the answer to. The best thing to do is to work through how you are coming to the answer aloud; justify your reasoning and show off your ability to think critically under pressure - think of it like an exam; "always show your working out". 

Google is one company that is well-known for delivering tricky interview questions. Here are some examples of questions they've asked in the past, along with some advice on how to tackle them:




1. "Estimate the number of tennis balls that can fit into a car."

Remember, it’s all about your methodology – they aren’t looking for an exact number. The interviewer probably doesn’t know the answer themselves. First, you might want to show you’re really thinking about it by asking some questions to make it easier to come to an answer, the most important of which being: what size car is it? From there, it’s just about coming to a logical estimation, talking through your process and then evaluating the answer you come to.


2. "How many times a day do a clock’s hands overlap?"

This one does have a correct answer. You might want to ask a qualifying question – are we just talking about the minute and hour hands, or the second one too? Then, even if you’re struggling to find the correct answer – do not panic. If you give up and just pull a number out of the air, you’ll come across as someone who doesn’t rise well to a challenge. Calmly explain your working and state your answer. The answer is 22, by the way.


3. "List 6 things that make you nervous."

You may get asked unusual personality questions, such as this one. The key is to remember to keep it work-related where possible; spiders or clowns aren’t strong answers. We recommend going with something along the lines of “sometimes I get really nervous speaking in front of big groups of people, but I’ve been working on this by doing X.” Accompanying each of the 6 ‘problems’ with a solution is your best bet.


4. "If you could be remembered for one sentence, what would it be?"

This question is also a gauge of your personality, and is an opportunity to implicitly show the interviewer something important about your values and aspirations. Think carefully.


5. "If you could choose one song to play every time you walked into a room for the rest of your life, what would it be?"

Again, this is a personal one and an opportunity to display desirable qualities to an employer. You can still approach it critically, though. You might want to think out loud about how the song will impact other people in every environment you walk into, including sensitive situations such as someone else’s wedding or an important business meeting. That is just one way to answer, but by doing so you can show you have an awareness of the feelings and needs of others and would work well as part of a team.


6. "How much would you charge to wash all the windows in [city name]?"

You can work this out via a series of estimations: how many people there are in the city, how many windows per person, how long it would take to wash one window and so on. If you’re not confident in your mental arithmetic ability you could settle on what you think a fair price per window would be. Of course, no matter what you say, you’ll be guessing, but it’s about how you come to that guess that matters.


7. "How many piano tuners are there in the entire world?"

This tests how well you react to being asked to give an answer when you have little to no information to go on. And, as with previous questions, it’s about putting together a series of estimates to come to a rough solution. How many people are there in the world? How many people per house on average? How many households have a piano? How often do pianos need tuning and how long does it take? State the assumptions you are making to get to your answer and ask for paper if you want to jot down some calculations. When you get to your answer, evaluate it. You can show your ability to self-critique and say “I’m not completely convinced by that answer, I think it’s actually less than that because…”


8. "Why are manhole covers round?"

No mental arithmetic involved in this one, but it does test your ability to problem-solve and come to a creative solution. There are a number of explanations you could go with: round manhole covers are easier to transport, or cheaper to manufacture (a square to cover the same sized hole would have a larger surface area), or so they won’t fall down the manholes. Whatever you say, as always, justify your answer thoroughly.


The key to these types of question is to show the interviewer you thrive under pressure, can think critically and can communicate and defend the answers you give effectively. It’s about the process, not the solution. 


Want to see how some university graduates got on when faced with these questions? Watch the full video by clicking below.