On Thursday, job search site Glassdoor published a list of 27 jobs with brain teasing interview questions–and not surprisingly, many of them are in the tech industry.

These types of questions can either hurt or harm an interview, Jen Teague, a small business staffing and onboarding coach told TechRepublic in December 2016. “When the interviewer has good grasp of the hiring procedures and what to look for, these can be very insightful as to how a candidate thinks,” Teague said. “However, when they are added for no purposeful reason, they will turn away good candidates. These are really good for STEM-related fields but not usually as appropriate for other industries.”

According to Glassdoor research, the difficulty of job interviews is determined by the number of interview screens, company size, the type of employer (public vs. private), education, and age. And, the tougher the job interview, the more satisfied an employee will be on the job, the research found: A 10% more difficult job interview process was associated with a 2.6% higher employee satisfaction rate later on. This is likely because a more rigorous interview process tends to yield a better employee match for the company, Glassdoor chief economist Andrew Chamberlain said in a press release.

Here are 27 difficult interview questions that tech job applicants might want to consider.

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1. “How do you explain a vending machine to someone who hasn’t seen or used one before?”

Global Data Analyst, Bloomberg L.P.

2. “How many fire hydrants are there in Los Angeles County?”

Software Engineer, Disney Interactive Studios

3. “If your current employer had an anniversary party for you, what five words would be written on the cake to describe you?”

District Manager, Express

4. “Who in history would you want to go to dinner with and why?”

Flight Attendant, PSA Airlines

5. “Prove that hoop stress is twice the longitudinal stress in a cylindrical pressure vessel.”

Test Operations Engineer, SpaceX

6. “What’s the capital of Canada?”

Team Leader, OpticsPlanet

7. “Name a brand that represents you as a person.”

Brand Strategist, Twitter

8. “Estimate how many employees are in the next building.”

Data Scientist, Risk Management Solutions

9. “How many happy birthday posts do you think Facebook gets in one day?”

Sales Operations, Facebook

10. “If you could take anyone on a road trip with you, who would you take and why?”

Educator, lululemon

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11. “What is the first thing you’d print with a 3D printer if you had one?”

Linux Systems Administrator I, Rackspace

12. “If you had to take only one item to a deserted island, what would that be?”

Customer Service Specialist, Squarespace

13. “Please describe an instance where you had to make a decision without all of the necessary information.”

Analytics, athenahealth

14. “How do you reverse a text string on the Unix command line?”

Developer, Capital One

15. “If you are in a boat with a boulder and you drop that boulder into the lake, how does the water level before and after you drop the boulder in the lake compare?”

Mechanical Design Engineer, Apple

16. “You have been asked to lead a multi-million dollar, multi-year grant that will be supported across several companies and universities. How do you start?”

Research Scientist, Ford Motor Company

17. “Sell me on one idea, and then sell me on the opposite of that idea.”

Solarwinds Administrator, Blizzard Entertainment

18. “How would you go about finding the top five Java Developers in a certain area?”

Technical Recruiter, Google

19. “What is the probability of an integer from 1 to 60,000 not having the digit 6?”

Quantitative Developer, AKUNA CAPITAL

20. “If you were a Muppet, which character would you be?”

Donor Family Advocate, LifeNet Health

21. “Give me 48 cents using six coins. Tell me quantity and value of the six coins.”

Human Resource Manager, Wintec

22. “Write an equation to optimize the marketing spend between Facebook and Twitter campaigns.”

Analyst (Data Science), Uber

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23. “What is the angle at 3:15?”

Implementation Consultant, Fast Enterprises

24. “What part of the newspaper do you read first? What does this say about you?”

Audit, BDO USA

25. “If a coworker had an annoying habit, and it hindered your quality of work, how would you resolve it?”

Production Technician, Procter & Gamble

26. “Throw your resume aside and tell me what makes you you.”

Sales Executive, Zillow

27. “How would you find the square root of 1.2?”

Hardware Engineer, Jump Trading