Have you ever heard of Puzzle interview questions?
It may come as a shock to you, but many interviewers ask puzzles and riddles to assess your critical thinking and problem-solving skills.
Popular in interviews for IT positions like software engineer, developer, programmer, coder, and computer programmer, this style is unique as it helps the recruiter find the perfect fit through interview puzzles.
These are logical thinking problems that enable the interviewee to use deductive reasoning skills to solve crucial, hard-to-answer questions.
Just like brain teasers, these puzzle questions test your wit, ability to perform in high-pressure situations, and creativity.
Even if you are not applying for a job in the IT sector, it is a great idea to prepare for puzzle interview questions as it can help you prepare for all kinds of tricky questions you may face.
So, here is a blog that will help you prepare best. Read on to discover the tricks and tips to face the puzzle interview and five popular questions with sample answers.
But first, we need to learn how to answer puzzle interview questions. Let’s get started!
How to answer puzzle interview questions?
Now that you are all set to learn more, here are a few things you can do to answer puzzle interview questions.
1. Take some time to think about the problem
Interviews can be nerve-wracking and candidates often rush into reacting to questions asked by recruiters.
It may work for you while answering common interview questions, but, it is always better to take a moment to think before answering, especially in the case of puzzle interview questions, as they can be a tad bit complicated.
So, the first thing you must do is take some time to gather yourself and understand the puzzle you are to solve.
If you think you need more than 10 seconds, you can ask the interviewer to give you a minute to solve the riddle and come up with the answer.
2. Feel free to ask for clarification
Puzzles and riddles can be confusing and hard to understand. So, make sure you get the question right before you go looking for answers.
In case you are worried about your impression in the eyes of the interviewer, we assure you that asking questions does not reflect poorly on you. Instead, it shows your curiosity and seriousness towards solving the puzzle.
3. Think about the puzzle with an open mind
No matter how trained you are at solving puzzles, some are always harder to solve than others, making it a tricky interview round.
If you get stuck, the best thing you can do is identify the type of puzzle and try to solve it from all angles possible. You may use traditional knowledge and techniques or experiment with something on the spot.
Even if you fail to find the solution, the interviewer will get to analyze your thought process and creativity by gauging your idea to solve the puzzle, which is the purpose of this interview.
4. Always explain your answer
If I ask you what is 2+2, you will immediately say 4. And this works great... unless you are in an interview.
The interviewers seek crisp, to-the-point answers from the candidates, but not without an explanation.
So, always explain your answer in detail. Talk about the premise, deduce the facts, and discuss how you would use them to find the solution.
It will reflect a methodically structured strategy, explaining how you arrived at the answer while showcasing your skills and ability.
5. Right or wrong, find a solution
This may sound bizarre, but while answering puzzle interview questions, it is better to give a wrong answer than not answering at all.
Even if you give an incorrect answer, the interviewer will be able to base their judgement on your logic and reasoning, which can be far more important than the actual answer.
Also, not providing an answer means that your attempt was unsuccessful. By completing the riddle, you would have concluded, completing your attempt.
5 Puzzle Interview Questions
There are a plethora of puzzles to be asked in a puzzle interview, making it very hard to know what to prepare. But you can always use similar methods and techniques to solve all questions.
Here are our five most favorite puzzle interview questions with answers to get you started.
1. You are stuck in a room with two doors- One right and one wrong. Both these doors are safeguarded by two guards, one in front of each door. The right door will lead you to your freedom and the wrong door will lead you to prison forever. However, you can ask both guards one question each. One guard always tells the truth, and the other guard always tells lies, but you don’t know which is which. What question should you ask to find the right door?
There are a couple of ways to answer this question. Let us take a look!
Sample answer 1
I would ask both the guards, “If I asked the other guard which is the right door, what would his answer be?”
Since both guards will point at the wrong door, I would skip that one and take the other one out.
Sample answer 2
I would ask one of the guards to open the door. Since I didn't open any door, I will not have to bear its consequences, and with this, I will be able to see what is beyond the said door, after which I will choose the right door.
2. A race track has five lanes. You are to find the 3 fastest horses out of a total of 25. How many races would have to be conducted to find the three fastest horses?
This puzzle interview question tests your approach and thinking abilities. Here’s how you can answer it.
Conduct 5 horse races with 5 horses in each group. Then, conduct another race with the winners of the said 5 races. The winner is the first fastest horse.
Then conduct another race with the rest of the 4 horses, and record the 1st and 2nd horses in it. They are the second and third fastest horses.
This way, you would have found the three fastest horses out of 25.
3. In the corners of an equilateral triangle are three ants. All the three ants move in a random direction along the triangle edges. Can you calculate the probability of ants not colliding at all along with the triangle?
There is a 50/50 probability that the ants will never meet and a 50/50 chance that at least two will.
As a result, the ants must all travel in either a clockwise or counter-clockwise direction, reducing your initial 50% chance of the ants colliding to a 25% chance since half of 50 is 25.
4. Two trains are running towards each other at a distance of 80km at a speed of 40km/h. A bird flies from train 1 towards train 2 at a speed of 100km/h. On reaching train 2, the bird covers the same distance back to train 1. If the bird keeps repeating this until the trains collide, how much distance would the bird have covered?
If you are tempted to calculate the distance from train 1 to train 2 back and forth and give that answer, trust us that it would not work in your favor.
It is a mathematical problem used to test your quick thinking, mathematics, and application of formulas. The answer to this question is,
The velocity of both trains approaching each other = 40km/h+40km/h= 80km/h
Time trains will take to collide= distance/velocity= 80km /80 km/h= 1 hour
So, the total distance travelled by the bird= Speed of the bird/ time taken by trains to collide= 100km/h*1hr= 100kms
5. You come across 100 closed doors in a straight line. You make 100 passes through each gate, starting with the first one. The first time you walk by a door, you open the closed ones and close the open doors. The second time you walk past the door, visit any door the first time you walk, and if it is closed, you open it, and if it is open, you shut it. You visit every other door on your second pass by, starting from the second, skip-counting them by two. In the 3rd pass, you go to every third door, in the fourth round to every 4th and so on. When reaching the 100th door, during your last round, which doors are open, and which are closed?
The number of the doors you pass will be the same as the divisor in the door's number. For example, if you pass by door number 27, consider its divisors 1,3,9, and 27.
Given that you will open the door on your first visit and close it on visiting the second time, you will open the door the first time you pass it, close it the third time, then open it again on the ninth pass, and finally closing it on your 27th pass.
Given that 27 does not have an exact square root, the door will be closed in the end. On the contrary, a number with a perfect square root like 9, will remain open. (Divisors are 1,3,9; so it will be open-close-open).
So the solution is that all door numbers with a perfect square root will be closed in the end, while those with a perfect square root will be open.
Tips for preparing for puzzle interview
After understanding the how, sample questions, and answers, here are some tips and tricks that will help you face puzzle interview questions.
1. Always keep a pen and paper in hand
Given the confusing nature of interview puzzles, you may miss out on crucial details. So, always keep a pen and paper handy.
That way, you will not have to worry about missing out on any information or confusing the numbers.
2. Practice, practice, practice
The saying Practice makes a man perfect fits well in interview scenarios. Puzzle interview questions are unique and can be hard to answer, but the one thing that can make it easy in practice.
So, read as many interview puzzles and solutions as you can before the interview and understand the process and logical reasoning involved in each answer.
3. Elaborate your problem-solving approach
The key to acing puzzle interviews is to explain your techniques and tactics in detail.
It helps the recruiter understand your thinking abilities and gauge your performance in tricky, time-critical situations.
So, when solving a puzzle interview question, make sure you discuss,
- The keynotes to solve the problem
- The method to solve the problem and the reason for choosing it
- The application of your theory
- Alternate methods
- The final result
With all these puzzle interview questions and answers, tips to ace a puzzle interview, and ideas on how to deal with it, you can stand out and land your dream job!
These interviews can be challenging, but remember to stay calm, have some water before the interview, and most importantly, take some time before you switch on your problem-solving mode.
All the best!