41 of Google’s Toughest Interview Questions
They get to enjoy free gourmet cafeterias, massage rooms, free health checkups, nap pods and so on. If they want to take a break, Google employees can relax by playing billiards, swimming in the company pool, enjoying some video games or giving the rock climbing wall a try.
Consequently, the company gets a lot of applications from job seekers.
To help it find the best employees from all these applicants, Google is known to have a very rigorous interviewing process, with difficult, brainteaser questions that require you to think outside the box.
These questions are thrown in between practical interview questions with the aim of testing how prospective employees act under pressure.
Many of these questions do not have any definite answer. Instead, they are meant to provide the interviewer with a glimpse into the interviewee’s problem solving skills and thought processes.
Below are the 41 toughest questions you might have to answer if you ever find yourself invited to an interview at Google.
1. How many golf balls can be fitted inside a school bus?
The aim of this question is to find out your approach to solving problems. Therefore, what matters is not the exact answer, but rather the thought process you follow to arrive at the answer.
To answer this question, you can guestimate the dimensions of an average school bus and then use these dimensions to calculate the volume of the bus.
From there, guestimate the volume of a golf ball and then divide the volume of the school bus by the volume of a golf ball to find out the number of golf balls that can fit inside the bus.
By explaining this process, you will have provided the interviewer with an insight into how you solve problems.
2. You need to confirm that your friend Bob has your correct phone number…
However, you cannot ask Bob directly. You have to write down the question on a piece of paper and give it to Eve, who will pass the paper to Bob and then pass back Bob’s answer to you. What should you write on the paper to ensure that Bob gets your message while making it impossible for Eve to find out your phone number?
This question is meant to test your creativity and your ability to think outside the box. A simple answer would be to ask Bob to give you a call.
If he makes the call, you will be certain that he has your correct number. If he doesn’t, then that means that he doesn’t have your number.
If you want to give an even more geeky answer, you can ask Bob to write down the sum of all the digits that make up your phone number. This is known as a check-sum.
If Bob doesn’t have your correct number, his answer will not be equal to the sum of all the digits of your number. In addition, since Bob will only write down the sum, it will be impossible for Eve to find out your number.
3. If you were asked to wash all the windows in Seattle, how much would you charge?
This is a trick question meant to test whether you can find simple solutions to complex problems. Instead of trying to guess the number of windows in Seattle, you can answer the question simply by stating the price you would charge per window, for example, $8 per window.
4. You are given eight balls which are equal in size…
Seven of these balls have an equal weight, while one ball is slightly heavier. You have also been provided with a weighing balance. How do you find the heavier ball in only two weighings?
The aim of this question is to test your ability to be creative in the face of limited resources. In this case, the answer is to first take 6 balls and place them on the weighing balance, three on each side.
If the balls balance each other, then you know that the heavier ball is not part of this group, and is therefore one of the remaining two balls. You can then put these two remaining balls on the balance to determine the heavier one. If the heavier ball is part of the six balls, one side of the balance will be heavier, and you will have narrowed down to the three balls on the heavier side.
You can now pick two balls from this group and place them on the balance. If the heavier ball is among the two balls on the balance, you will know which one it is. If the two balls balance each other, then the third ball is the heavier one.
5. Come up with an evacuation plan for this city.
This is another question that is meant to provide the interviewer with a glimpse into your thought processes while solving problems.
The best response to this question would be to first ask the kind of disaster you are planning for.
6. How many piano tuners are there in Chicago?
Once again, this question is meant to test your thought processes when solving problems. What matters is not giving an exact answer, but rather explaining the thought process that led you to the answer.
To answer this question, you should start by making a guestimate of the total population of Chicago.
From the total population, you can come up with an estimate of the number of households within the city.
Next you need to make an estimate of the number of households that own a piano.
From there, estimate the number of times that a piano is tuned each year. From this, you can come up with an estimate of the number of piano tunings that are done each year.
From there, make an estimate of the average time it takes for a piano tuner to tune the piano.
Assuming that each piano tuner works 8 hours a day for 5 days a week, it is possible to calculate the number of piano tuners within the city.
7. There are four people stranded at night on one side of a cliff who need to go across a rickety rope bridge…
Unfortunately, the group has only one flashlight, and the batteries on the flashlight can only keep it powered for 17 minutes. Crossing the bridge without a flashlight is too dangerous, and the bridge can only support two people at a time. The four people have different speeds of going across the bridge. The first person can cross the bridge within a minute. The second one needs two minutes to cross the bridge. The third person needs 5 minutes to cross the bridge, while the last person needs 10 minutes to go across the bridge. How can the group make it across the bridge before the batteries on the flashlight die?
This question is simply a riddle meant to test your creativity. The correct answer is to have person one and two cross the bridge together, taking two minutes.
Person one goes back with the flashlight, with three minutes spent so far. Person three and four then cross together in ten minutes, taking the total time spent to 13 minutes.
Person two would then go back with the flashlight, taking total time spent to 15 minutes.
Person one and two would then cross the bridge together in the two minutes remaining before the flashlight goes off.
8. Assume you are the captain of a pirate ship and you have just stolen some loot from another ship…
As the captain, you get to decide how the loot will be divided. However, the crew will have to vote on your decision. If more than half of the crew vote against your plan, you will be killed. How will you recommend that the loot be divided in such a way that you stay alive and still get a good share of the loot?
This question aims to test your ability to come up with solutions for problems that deal with consensus in computing. This question is usually directed to engineering managers.
The answer to this question is to divide the loot evenly between 51% of the crew.
9. Your body is reduced in size to the height of a nickel and then you are thrown into an empty blender. The blender will be turned on in 60 seconds. What will you do?
This is another question that is meant to test your creativity. Like many of the questions, there is no definite answer to this question.
You could try and tamper with the electric motor before the blades start moving.
10. Explain a database to your 8 year old nephew in three sentences
The aim of this question is to test your understanding of complex ideas and your ability to explain these ideas in simple language.
A simple answer to this question would be: “A database is a machine where you can store lots of information about something. You can then go to this machine whenever you want to remember that information.”
11. How much money does Google make from Gmail ads daily?
This question is meant to test your knowledge of Google’s different revenue systems as well as your analytical skills. What matters here is not the exact answer, but your explanation of how you arrive at your answer.
For instance, you might start your answer by stating the number of ads that Google places in each opened Gmail email. You can then estimate the average amount advertisers pay for each click on the ads.
From this, you can calculate the amount of money Google makes daily from Gmail ads by multiplying the number of Gmail users by the average number of emails each user receives each day by the average rate paid per clicked ad, divided by the multiple of email open rate and click through rate.
12. What is the weight of the empire state building?
This is another question that is meant to test your thought processes.
Once again, the aim here is not to give the exact weight of the empire state building. Unless you had anticipated the question and googled the question, it would be impossible to know the exact weight.
What you want to do in case this question is asked is to explain how you would go about calculating the weight of the building.
13. If the time on a wall clock is 3:15, what is the angle between the minute hand and the hour hand?
This is a trick question that whose aim is to test your attention to detail. Many people are likely to say the angle is zero since 3 o’clock and 15 minutes past the hour are both represented by the number 3 on a clock.
However, you should keep in mind that the hour hand gradually moves to the next number as the hour progresses. Therefore, while the minute hand will be pointing at 3, the hour hand will be a quarter way between 3 and 4.
Since there are 60 minutes in one revolution of the minute hand, we can say that each minute is equal to 6 degrees.
Therefore, the angle between two numbers on the clock is 30 degrees. Since the hour hand is ¼ way between 3 and 4, while the minute hand is at 3, the angle between them will be ¼ of 30 degrees, which is 7.4 degrees.
14. What should we have for dinner tonight?
Yes, this is actually a question that has been asked during a Google interview. The aim of this question is to test your ability to be a leader.
Therefore, you should give a definite answer, instead of saying something like “Depends on what you like” or “what do you have in mind?”
15. What is the significance of “dead beef”?
This question is usually asked to computer engineers with the aim of testing your knowledge of the industry.
Don’t respond by saying that beef is always dead.
Instead, you should be aware that DEADBEEF is a computing term that refers to a hexa-decimal value that was used to debug mainframe computers.
16. Is your IQ more than 130?
This is a trick question that is meant to assess your intellectual humility and how you view yourself.
Avoid answering this question with a yes even if you know your IQ is above 130.
People who take IQ tests and remember the results are likely to be insecure and prone to self-aggrandizement.
17. There are months with 30 days and others with 31 days. How many months have 28 days?
This is another trick question. Don’t be tempted to give “February” as your answer, because all months have 28 days or more.
18. You are presented with six glasses arranged in a row…
The first three glasses are empty, while the next three glasses are full of juice. You are required to arrange these glasses such that empty glasses alternate with full glasses. You are only allowed to move one glass. How do you do it?
This question is meant to test your creativity. The correct answer is to take the fifth glass, which is full, and pour its contents into the second glass.
19. You want to bring your dog to the office but one of your colleagues is allergic to dogs. What will you do?
The aim of this question is to assess how you would deal with potentially conflicting situations between you and your colleagues. A good answer would be to either leave your dog at home or ask to work remotely.
20. Between a flower shop and a funeral home, which has greater advertising potential?
Advertising is one of Google’s main sources of revenue, so this question tests your understanding of the company’s business model.
When answering this question, you should explain why you think one has greater potential than the other.
For instance, you could say that the funeral home has greater advertising potential because it has a well-defined target audience and buyer intent keywords.
21. What do you think the term being Googley means?
This question is meant to test whether you have a good understanding of company culture at Google. Google looks for crazy but innovative nerds. T
herefore, being Googley would mean being a crazy nerd who would fit at Google.
22. If you got this job, what prank would you pull on your manager?
This is another question that is meant to test your personality and your knowledge of company culture.
Most Googlers are a fun lot to work around, therefore the company wants to know if you are the kind of person who would fit in such a group.
However, I don’t think pulling a prank on your manager is such a good idea.
23. You have a piece of paper that is 1mm thick. How many times would you need to fold the piece of paper in half for it to be high enough to reach the moon?
This is a trick question that is meant to test how you react when faced with an unexpected question, as well as to assess how well you understand situations that involve exponential growth.
While it would be really difficult to come up with the correct answer during an interview, the answer is 42. Folding a 1mm thick piece of paper in half 42 times will make the paper 4,398,046 km in height, which is more than the distance from the earth to the moon.
24. Why are manhole covers round?
This is a pretty common question in Google interviews, and it’s surprising that many people do not know the answer. Manhole covers are round because a circle is the only shape that cannot fall through itself.
25. If you had to remove ads from YouTube, how would you continue making money from the platform?
This question is meant to test your knowledge of monetization options available in the digital space. Here, you can talk about options like creating a premium version of the platform, or charging content creators to post on the platform.
26. How would you explain the internet to someone who has absolutely no clue what it is?
This question is meant to test your knowledge of the internet – the chief space in which Google operates – as well as your communication skills.
27. You are at a party where there are 10 people, including you and a friend…
Your friend proposes a wager where you get $1 for every person in the party who shares their birthday with you, while he gets $2 for every person who has a different birthday from you. Would you take up the wager?
Unless there’s a seasonal increase in births around the month you were born, you should avoid this wager, since the probability of someone sharing the same birthday as you is 1/365.
28. What would you spend your time doing if working was not necessary?
If you did not have to work to earn a living, you would definitely spend time doing the things you love. This question is meant to give the interviewer some insight into your passions.
29. What would I learn about you by opening your browser history?
This question is similar to the previous question in that it tries to understand your passions and interests. Of course, most people spend the highest percentage of their time online on things that interest them.
30. Assume an advertiser makes $0.10 every time an ad is clicked. Only 20% of visitors click on this ad. How many people does the advertiser need to visit the site in order for him to make $20?
Such a question might seem easy, but it can be pretty confusing when you are sitting nervously before a panel. The answer to this question is 1000 people.
31. Which is your favorite product from Google, and how would you make it better?
This question is meant to test your understanding of Google’s products. If you are going for an interview at Google, you definitely need to know how most of their products work.
32. How many ways are there for finding a needle in a haystack?
The aim of this question is to test your ability to be creative and to think outside the box. The answers to this question are as many as you can think of.
You might opt to use a metal detector, you might choose to burn the haystack at a temperature that leaves the needle intact while reducing the hay into ashes, or you might decide to painstakingly go over each straw of hay, though this might take you several months to find the needle.
33. What changes do you think will happen in the digital advertising space in the next 3 years?
Advertising is one of Google’s core sources of revenue, and therefore you need to have a good understanding of digital advertising if you want to work at Google.
This question is meant to test your understanding of digital advertising and to test whether you are up to date with the trends in the industry.
34. How would you describe AdWords to a 7 year old?
This question is meant to test your understanding of how AdWords works and your ability to explain a complex feature in simple language.
35. How many haircuts are made annually in the United States?
Yes, this is another of those seemingly impossible questions that will pop up during an interview at Google. Here, the aim is to find out your thought processes, rather than the actual number of haircuts that are made in the US every year.
Here you can make a guestimate by making some assumptions.
For instance, you might assume that the average American gets a haircut every two months, which is a total of about six times every year. Multiplying this by America’s population will give you a ball park figure of the number of the number of haircuts that happen in the country every year.
36. If you had to explain the importance of HTML to Sergey Brin and then to your grandmother, how would you do it?
The aim of this question is to test your communication skills. It tests your ability to explain a complex concept both in technical terms and in layman’s language.
When explaining to Sergey Brin, you would use technical language because he is a computer scientist.
However, when explaining to your grandma, you would have to use layman’s language because she probably would not understand the technical terms.
37. Do you prefer learning or earning?
This question tries to assess whether you care more about improving your skills or making money. If you want to work at Google, you have to show a commitment to continuous improvement of your skills.
However, this doesn’t mean that you should pay zero attention to your income. A good answer would be: “I prefer a position that allows me to work (earn some money) while learning new things.
38. If you had $10 million in your account, how would you spend it?
Ever heard of the saying ‘show me where you spend your money and I will tell you what your values are’? This question is meant to give the interview an insight into what your greatest priorities are.
39. If you are given a spacecraft and $1 billion, how would you solve mankind’s biggest problem?
Google X’s moonshot projects are aimed at using technology to solve some of the world’s biggest problems. If you answer this question properly, you might end up getting sent to Google X’s top secret research lab in California.
40. How many times do the hands of a clock overlap each day?
This question is asked to simply present you with an unexpected question and see how you react under pressure. Don’t stare at the interviewer in bewilderment. The hands of a clock overlap 22 times every day.
41. Would it be a good idea for Google to start charging Gmail users $1 per month?
The aim of this question is to test your knowledge of the dynamics of monetizing a service like Gmail. Charging users $1 per month would probably not be a very good idea, since the cost of introducing and processing the payments would keep the venture from being profitable.
The fee would also lead to a decrease in the number of Gmail users.
These are some of the tough questions that might get thrown your way in case you find yourself interviewing at Google.
Knowing the kind of questions that are asked will help you prepare for all kinds of scenarios so you don’t find yourself bewildered once you are asked to state the weight of the empire state building.
However, many of the big companies are abandoning these kinds of questions because they are not accurate predictors of job performance, and hopefully, Google will also have abandoned them by the time you get invited for an interview.