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Table of contents
1.
Introduction
2.
Easy Level Brain Teaser Interview Questions
2.1.
1. Ninja is standing behind you and you are standing behind the Ninja. How is this possible?
2.2.
2. In a race, Ninja overtakes Rohan, who is in the second position. What is the current position of the Ninja?
2.3.
3. Ninja’s mother has four sons: April, May and June. What is the name of the fourth child?
2.4.
4. Why are maintenance hole covers round?
2.5.
5. Before Mount Everest was discovered, which was the highest mountain?
2.6.
6. Eskimos are good at hunting, but they never hunt penguins. Why?
2.7.
7. A bacteria doubles every minute. If the petri dish was full at 10 AM, at what time was it half filled?
2.8.
8. A doctor’s son’s father was not a doctor. How is this possible?
2.9.
9. What is the number in the place of the question mark: 125, 64, 27, 8?
2.10.
10. Build one word from the jumbled arrangement of alphabets : D O W R N O E
3.
Medium Level Brain Teaser Interview Questions
3.1.
11. Describe the red colour to a blind person.
3.2.
12. In one year, how much cheese is sold by Dominos? 
3.3.
13. How much should you charge to wash all windows in Bangalore?
3.4.
14. A woman was born in 1947 but is only 30 years old now. How is this possible?
3.5.
15. How many people are using Instagram in Delhi at 1:30 pm on a Thursday?
3.6.
16. What is the sum of numbers from 1 to 100?
3.7.
 17. How many footballs would fit in an Airbus A380?
3.8.
18. A train can hold q people. It was half vacant from the start, and at the first station, y people got off. How many travellers can now get on the train?
3.9.
19. “Sell me this Macbook?”
3.10.
20. Is it better to seek perfection and be late or be good and on time?
4.
Hard Level Brain Teaser Interview Questions
4.1.
21. You are blindfolded and given ten coins, with five coins in the head and the other five in the tails position. The only operation you can perform is to flip the coins. How will you ,divide the coins into two groups with an equal number of heads?
4.2.
22. You are given a black box containing three pairs of balls of Red, Green and Blue colour respectively. What must the minimum number of balls be drawn to get a couple of balls of the same colour?
4.3.
23. You must fill the boxes below with consecutive numbers from 1-8, without repetition, and use all the numbers exactly once. Note: consecutive means that no two boxes should have consecutive numbers in all eight directions, i.e. including diagonal boxes.
4.4.
24. You are in a room with three switches which are connected to three bulbs in other rooms. You can only go once to the other room. How will you find out which bulb is related to which switch?
4.5.
25. You were kidnapped by a gangster. He put two consecutive bullets and randomly rolled the revolver. He took the first shot, and luckily you survived. He asked you if he should roll it again or not. What will you say?
4.6.
26.  You are given two containers with 3 and 5 litres capacity. How will you measure 4 litres using these containers?
4.7.
27. It is always 1 to 6, always 15 to 20, but it is never 21 unless it is flying? What is this?
4.8.
28. By travelling at 40 mph, a person reaches his destination on time. He covered two-thirds of the entire distance in one-third of the entire time. What speed should he maintain for the remaining length to reach his destination on time?
4.9.
29. In a group of 15 students, 7 have studied Android Development, 8 have studied Machine learning, and three have not studied either. How many of these studied both Android and Machine Learning?
4.10.
30. An explorer found a silver coin marked 7 BC. He was told it was a forgery. Why?
5.
Frequently Asked Questions
5.1.
What are brain teaser interview questions?
5.2.
What are examples of brain teasers?
5.3.
What is a brain teaser for a finance interview?
5.4.
What skills do you need to answer brain teasers?
6.
Conclusion
Last Updated: May 17, 2024
Easy

Brain Teaser Interview Questions

Author Manish Kumar
1 upvote
Create a resume that lands you SDE interviews at MAANG
Speaker
Anubhav Sinha
SDE-2 @
12 Jun, 2024 @ 01:30 PM

Introduction

Brain teasers are no to so frequently asked in tech interviews. But when they do appear, they are the ones who decide whether you will land your dream job or not. So it is always good to stay ready for any situation. Brain teaser interview questions assess an applicant's critical thinking, problem-solving and listening capabilities. These brain teaser interview questions will give you an edge for sure!! 

The most vital and likely brain teaser interview questions will be covered in this blog.

Brain Teaser Interview Questions

Easy Level Brain Teaser Interview Questions

This section contains the basic brain teaser interview questions to build a solid foundation. This section is crucial since it establishes a strong base for logical thinking.

1. Ninja is standing behind you and you are standing behind the Ninja. How is this possible?

Ans: You and Ninja are standing with yours backs towards each other.  
 

Interview Tricks

 

2. In a race, Ninja overtakes Rohan, who is in the second position. What is the current position of the Ninja?

Ans: You might instinctively say first, but the answer is second. Rohan will now be at 3rd position and Ninja at second.

race track

 

3. Ninja’s mother has four sons: April, May and June. What is the name of the fourth child?

Ans: Fourth son's name is Ninja.

 

Month names

4. Why are maintenance hole covers round?

Ans: Maintenance holes are round because they cannot fall through themselves. Another good answer could be it is easy to manufacture and is aesthetically more pleasing than any other shape. 

maintenance hole covers

5. Before Mount Everest was discovered, which was the highest mountain?

Ans: Mount Everest. It was just discovered later.

 

6. Eskimos are good at hunting, but they never hunt penguins. Why?

Ans: Eskimos live at the north pole and penguins in the south pole region.

south pole penguins

7. A bacteria doubles every minute. If the petri dish was full at 10 AM, at what time was it half filled?

Ans: Don't consider the exponential growth. Instead, follow the logic. The answer is 9:59 AM.

 

8. A doctor’s son’s father was not a doctor. How is this possible?

Ans: Mother is the doctor. This question is to trick you and make you think that the father is the doctor.

doctor

9. What is the number in the place of the question mark: 125, 64, 27, 8?

Ans: 1: The sequence shows cube roots of numbers in decreasing order.

 

10. Build one word from the jumbled arrangement of alphabets : D O W R N O E

Ans: ONE WORD

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Medium Level Brain Teaser Interview Questions

We discussed some of the easy-level brain teaser interview questions. Let us now go through some of the medium-level Brain Teaser Interview Questions. 

11. Describe the red colour to a blind person.

Ans: Red is the colour of the scorching sun, the anger when frustrated and anything dangerous. 

 

12. In one year, how much cheese is sold by Dominos? 

Ans: To answer this question, think about the number of pizzas sold by Dominos every year. How much cheese is utilised on average per pizza? Then find the required answer by multiplying them. The answer should be based on facts and not on any random assumptions.

domain name

13. How much should you charge to wash all windows in Bangalore?

Ans: This is a hypothetical question. One good answer can be we don’t need to wash windows as Banglore gets a good amount of rain. Another approach can be based on guessing the number of houses using the city’s population and multiplying it by the charge per window.

hypothetical question

14. A woman was born in 1947 but is only 30 years old now. How is this possible?

Ans: Since the given year is logically not possible. Think in the direction that 1947 is not a year but a room number in the hospital or any other possible solution.

Year Gate

15. How many people are using Instagram in Delhi at 1:30 pm on a Thursday?

Ans: This question will test your guessing capability, knowledge of Instagram users in urban areas, and whether you can change your estimates based on time and the weekday.

 

16. What is the sum of numbers from 1 to 100?

Ans: This question is intended to test the speed of your mathematical thinking skills. The trick is to have 50 pairs each sum to 101 (e.g. 1+100, 2+99, 3+98, etc.). So, 50 times 101 = 5050.

 

 17. How many footballs would fit in an Airbus A380?

Ans: This one is tough. The interviewer wants to see your approach rather than the exact figure. The way you approach it is more important. Your critical thinking is judged here. Try to go with a logical process, such as assuming the correct volume of football and the aeroplane, whether the seats are attached to the plane or if it is empty.

Airbus A380

18. A train can hold q people. It was half vacant from the start, and at the first station, y people got off. How many travellers can now get on the train?

Ans: Initially, q/2 seats were empty. After the first station, y people left, so the remaining capacity is q/2+y.

 

19. “Sell me this Macbook?”

Ans: This question is a brain teaser, and a sales question simultaneously. Don't get overwhelmed, and keep calm. You already know the device's pros because you own it, emphasize it, and discuss its benefits. Try to frame it in a vivid picture and give the answer accordingly.

 

20. Is it better to seek perfection and be late or be good and on time?

Ans: The answer to this question primarily depends on the interviewer but as a rule of thumb, go with the 'good and on time' option as managers do not like to extend deadlines often.

Hard Level Brain Teaser Interview Questions

This section will discuss some of the most challenging Brain Teaser Interview Questions. While knowing easy and medium-level questions is necessary, the complicated questions will set you above other candidates in the interview. Let us go through some of the most difficult Brain Teaser Interview Questions.

Brain Teaser Interview Questions

21. You are blindfolded and given ten coins, with five coins in the head and the other five in the tails position. The only operation you can perform is to flip the coins. How will you ,divide the coins into two groups with an equal number of heads?

Ans: First of all, divide the coins into two groups of five coins each. Now flip the coins of one entire group. Now we have two groups with an equal number of heads. Let's understand it with an example:

Initial orientation: HHTHT-HHTTT

Final orientation: HHTHT-TTHHH 

Image Hint

22. You are given a black box containing three pairs of balls of Red, Green and Blue colour respectively. What must the minimum number of balls be drawn to get a couple of balls of the same colour?

Ans: Let us go through the worst case:

  • Suppose you took out a ball at random, and it was red.
  • You took out another ball, and it was yellow.
  • The third ball you took out was green.
  • Now in the fourth attempt, you will get a pair with matching colour.
     

The answer to this question is four balls.

 

23. You must fill the boxes below with consecutive numbers from 1-8, without repetition, and use all the numbers exactly once. Note: consecutive means that no two boxes should have consecutive numbers in all eight directions, i.e. including diagonal boxes.

Question Image

Ans: The only solution for the above design is given below: 

Answer Image

 

24. You are in a room with three switches which are connected to three bulbs in other rooms. You can only go once to the other room. How will you find out which bulb is related to which switch?

Ans: Turn on a switch for 5 minutes and then switch it off. Turn another switch off and then go to the other room. Now the turned-on bulb is mapped with the currently ON switch. The warm bulb corresponds to the initially turned ON switch. And the remaining button is for the third bulb.

3 switches

25. You were kidnapped by a gangster. He put two consecutive bullets and randomly rolled the revolver. He took the first shot, and luckily you survived. He asked you if he should roll it again or not. What will you say?

Ans: Here, the interviewer wants to judge if you give an answer based on facts or not. And if you answer with some logic, then it would be the best answer. The reason is based on the probability of two consecutive bullets. If it is in its initial state, the likelihood of survival is 33%, but if the first shot went empty, it drops to 25%. So, your answer should be rolling it again.

26.  You are given two containers with 3 and 5 litres capacity. How will you measure 4 litres using these containers?

Ans: Take the 3 litres container and fill it. Now, empty it into 5 litres container. Again take the 3 litres container, fill it up and now pour it into a 5 litres container until it is filled completely. 

At this stage, 3 litres container contains 1 litre of liquid.

Now, remove everything from the 5-litre container. Pour 1-litre liquid from the 3-litre container into 5 litre one. Again, fill up the 3 litres container and pour them entirely into the 5 litre container. 

Now you have exactly 4 litres of liquid in the 5 litres container.

 

27. It is always 1 to 6, always 15 to 20, but it is never 21 unless it is flying? What is this?

Ans: A dice: the sides of the dice are numbered 1 to 6, and the sum of exposed faces is between 15-20 when placed on a flat surface. The sum of all the faces is 21 when it is flying.

Dice

28. By travelling at 40 mph, a person reaches his destination on time. He covered two-thirds of the entire distance in one-third of the entire time. What speed should he maintain for the remaining length to reach his destination on time?

Ans: 20 mph

Let the time taken to reach the destination be 3x hours. Total distance = 40 * 3x = 120x mile.
He covered 2/3 * 120x = 80x miles in 1/3 * 3x = x hours.
So, the remaining 40x mile he has to cover in 2x hours would be the required speed = 40x / 2x = 20 mph.

 

29. In a group of 15 students, 7 have studied Android Development, 8 have studied Machine learning, and three have not studied either. How many of these studied both Android and Machine Learning?

Ans: 3

 

30. An explorer found a silver coin marked 7 BC. He was told it was a forgery. Why?

Ans: You can never have a 7 BC mark because Christ didn’t exist yet, and nobody knew who Christ was back then.

Check out this problem - Minimum Coin Change Problem 

Frequently Asked Questions

What are brain teaser interview questions?

Brain teaser interview questions are challenging puzzles or problems designed to test a candidate's critical thinking, problem-solving skills, and creativity. They often have non-obvious solutions that require logical reasoning and lateral thinking.

What are examples of brain teasers?

Examples of brain teasers include puzzles like, "How many golf balls can fit in a school bus?" or logic problems like, "Why are manhole covers round?" These questions assess a candidate's ability to think outside the box.

What is a brain teaser for a finance interview?

A common finance interview brain teaser might be, "How would you value a company with no revenue?" This question tests a candidate's understanding of financial principles and their ability to apply creative thinking to valuation methods.

What skills do you need to answer brain teasers?

To answer brain teasers effectively, you need strong analytical skills, logical reasoning, creativity, and the ability to think under pressure. These skills help in approaching the problem from different angles to find a solution.

Conclusion

In this blog, you learned about the top brain teasers interview questions. All the important topics related to brain teasers interview questions were covered in detail.

Also, do refer to other Interview Questions related articles:

After reading these brain teasers interview questions, are you not feeling confident to crack any interview? We hope you enjoyed reading our brain teaser interview questions blog.

You can also consider our Interview Preparation Course to give your career an edge over others.

Please upvote our brain teasers interview questions blog if you found it helpful and informative!

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