How many of Google's banned interview questions can you get right?

Google definitely has a history of asking out-of-the-box questions and brain teasers at their interviews. And as reported in 2011, some of the questions were so tough that they were banned from the company.

Lewis Lin, a career consultant who specializes in interview techniques, compiled a list containing 140 questions some of his clients were asked by Google. They were applying for jobs like product managers, software engineers, and marketing managers. The thing about these questions is that most don't strictly actually have an answer but are instead designed to test creativity and assess how you tackle the question. 

Get ready for your job interview, here are some of the hardest questions (answers at the bottom):

1. How much should you charge to wash all the windows in Seattle?

2. Why are manhole covers round?

3. You need to check that your friend Bob has your correct phone number, but you cannot ask him directly. You must write the question on a card and give it to Eve who will take the card to Bob and return the answer to you. What must you write on the card, besides the question, to ensure that Bob can encode the message so that Eve cannot read your phone number?

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

5. Every man in a village of 100 married couples has cheated on his wife. Every wife in the village instantly knows when a man other than her husband has cheated but does not know when her own husband has. The village has a law that does not allow for adultery. Any wife who can prove that her husband is unfaithful must kill him that very day. The women of the village would never disobey this law. One day, the queen of the village visits and announces that at least one husband has been unfaithful. What happens?

6. A man pushed his car to a hotel and lost his fortune. What happened?

7. How many times a day does a clock's hands overlap?

8. How many vacuums are made per year in the USA?

9. Explain the significance of "dead beef."

10. If a person dials a sequence of numbers on the telephone, what possible words/strings can be formed from the letters associated with those numbers?

11. You are shrunk to the height of a nickel and your mass is proportionally reduced so as to maintain your original density. You are then thrown into an empty glass blender. The blades will start moving in 60 seconds. What do you do?

12. How many golf balls can fit in a school bus?

13. Explain a database in three sentences to your 8-year-old nephew.

14. You have to get from point A to point B. You don't know if you can get there. What would you do?

15. You are at a party with a friend and 10 people are present (including you and the friend). Your friend makes you a wager that for every person you find who has the same birthday as you, you get $1; for every person he finds who does not have the same birthday as you, he gets $2. Would you accept the wager?

Um, is anyone else confused AF? If you can't be bothered working them out, we can now reveal the answers:

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

The riddle is known as a Fermi problem, named after the physicist Enrico Fermi.

The puzzle is solved by multiplying a series of estimates to get to the right answer.

So a candidate would have to estimate factors such as how many households have a piano, how often they are tuned to figure out how many piano tunings take place a year.

They then need to calculate the average working hours of a piano tuners and the number of jobs they carry out.

The number of piano tunings that take place per year divided by the number per year per piano tuner should yield the answer.

2. How many golf balls can fit in a school bus?

To solve it one must calculate the volume of the average golf ball and the the volume of the average school bus, taking into account factors like the seats and other fixtures taking up space.

The answer is the volume of the bus, divided by the volume of the balls.

3. How many times a day do the hands of a clock overlap?

The hands overlap once an hour, but 11 times in 12 hours and 22 times in a day.

This is because the overlap at 12 has already been accounted for.

The overlaps occur at 12, 1.05, 2.11, 3:16, 4:22, 5:27, 6:33, 7:38, 8:44, 9:49 and 10:55 in the morning and after midday at 12, 1.05, 2:11, 3:16, 4:22, 5:27, 6:33, 7:38, 8:44, 9:49 and 10:55.

4. You are shrunk to the height of a nickel and your mass is proportionally reduced so as to maintain your original density. You are then thrown into an empty glass blender. The blades will start moving in 60 seconds. What do you do?

There are numerous possible answers to this one - lie down until the blades stop, or even climb onto the blades before they start.

Some suggest that a human shrunk down to such proportions would effectively have superpowered-muscles that would enable them to jump out of the blender.

5. You have to get from point A to point B. You don't know if you can get there. What would you do?

As an incredibly vague question, there are numerous possible answers.

The obvious starting point is to determine what points A and B are and whether they are actual physical locations or simply figures of speech.

From there, a route could be plotted relying on known travel times, or slightly less tangible course of action could be planned.

6. Imagine you have a closet full of shirts. It's very hard to find a shirt. So what can you do to organize your shirts for easy retrieval?

There is no one answer to this, but the question was aimed at software engineers.

Therefore, the interviewer would expect a coding-based approach, such as assigning different values to different types of shirts, by style, colour and fit.

7. Explain the significance of 'dead beef'.

Most software engineers would be aware of this term which refers to a hexadecimal code used in debugging computer systems.

8. How much should you charge to wash all the windows in Seattle?

An educated guess is required for this one, based on the number of buildings with windows in the city.

For example, if the interviewee assumes that Seattle consists of 10,000 city blocks with around 600 windows each, and that it takes five minutes to wash a window at a rate of $20, then the total cost would be around $10 million.

9. If you look at a clock and the time is 3:15, what is the angle between the hour and the minute hands?

The answer is 7.5 degrees. The hour hand moves 360 degrees around the clock every 12 hours, or 30 degrees per hour.

So in the fifteen minutes between 3:00 and 3:15, it will have moved 7.5 degrees - one quarter of 30 degrees.

The minute hand will be pointed directly at the three, so the distance between them is 7.5 degrees.

10. A man pushed his car to a hotel and lost his fortune. What happened?

The car was a piece in the board game Monopoly.

- Daily Mail