The earlier you land up to the industry which interests you, the better it is for your carrer. I landed up into analytics industry by chance. When I joined my first firm, I was aware what analytics means, but did not really know how big is the opportunity to grow in this industry. Now, I know that things happened for the best (although by chance). Analytics industry relies on extensive use of statistics and Data handling tools. But, these skills are really not expected from freshers moving into this domain. Hence, it becomes really difficult for the employers to conclude if a candidate will do well in the industry or not. Primarily what they are interested in is the number crunching skills and the structured thinking capabilities.
To gauge these skills, employer generally use any of the following three types of questions :
2. Business Case study
3. Guess estimate
We have published a number of articles on the approaches to take in solving Business Case study and Guess estimate problems. However, we have still not covered the first category of questions i.e. Puzzles. Puzzles are not the ideal way to judge analytical skills because you will be able to solve the question, if you already know it. Solving from scratch is the tougher bit.
Because there are a limited number / type of puzzles which are in use, knowing / practicing them before hand can really become your strength in analytics interviews. In this article, we will solve three widely asked puzzle questions in these interviews.
Take the Test: Should I become a Data Scientist?
Two trains X and Y (80 km from each other) are running towards each other on the same track with a speed of 40km/hr. A bird starts from the train X and travels towards train Y with constant speed of 100km/hr. Once it reaches train Y, it turns and starts moving toward train X. It does this till the two trains collides with each other. Find the total distance traveled by the bird?
Maximum time to solve the puzzle : 1 Minutes
Difficulty level of the puzzle : Low
What is the interviewer looking for : Your approach. If you start calculating distance from X to Y and the Y to X and so on, you have already been rejected.
Solution : Velocity of approach for the two trains = (40 + 40) km/hr
Total time the trains will take to collide = 80km/80km/hr = 1 hour
Total distance travelled by the bird = 100km/hr * 1hr = 100 km.
You have two beakers – one of 4 liters and other of 5 liters. You are expected to pour exactly 7 liters in a bucket. How will you complete the task?
Maximum time to solve the puzzle : 2 Minutes
Difficulty level of the puzzle : Medium
What is the interviewer looking for : Answer.
Step 1 : Fill in 5 liter beaker and empty it in the 4 liter beaker. You are left with 1 liter in the 5 liter beaker. Pour this 1 liter in the bucket.
Step 2 : Repeat step 1 and you will have 2 liters in the bucket.
Step 3 : Fill in the 5 liter beaker and add to the bucket.You now have 7 liters in the bucket.
There are 5 pirates in a ship. Pirates have hierarchy C1, C2, C3, C4 and C5.C1 designation is the highest and C5 is the lowest. These pirates have three characteristics : a. Every pirate is so greedy that he can even take lives to make more money. b. Every pirate desperately wants to stay alive. c. They are all very intelligent.
There are total 100 gold coins on the ship. The person with the highest designation on the deck is expected to make the distribution. If the majority on the deck does not agree to the distribution proposed, the highest designation pirate will be thrown out of the ship (or simply killed). Only the person with the highest designation can be killed at any moment. What is the right distribution of the coins proposed by the captain so that he is not killed and does make maximum amount?
Maximum time to solve the puzzle : 15 Minutes
Difficulty level of the puzzle : High
What is the interviewer looking for : Your approach and solution structure.
Solution : The solution of this problem lies in thinking through what will happen if all the pirates were thrown one by one and then thinking in reverse order.
Let us name pirates as A,B,C,D and E in hierarchy (A being highest).
If only D and E are left at end, D will simply give 0 coins to E and still escape because majority cannot be reached. Hence, even if E gets 1 coin he will give his vote to the distributor.
If C, D and E are there on the deck, C will simply give one coin to E to get his vote. And D simply gets nothing. Hence, even if D gets 1 coin he will give his vote to the distributor.
If B,C,D and E are there on the deck, B will simply give one coin to D to get his vote. C & E simply gets nothing.
If A,B,C,D and E are there on the deck, A simply gives 1 coin each to C and E to get their votes.
Hence, in the final solution A gets 98 coins and only C & E get 1 coin each.
If you were able to solve all the 3 puzzles, (from scratch) you have a good hunch for such puzzles. In case you were not able to crack the last one, you simply need to practice more. In case you were not able to crack two of the puzzles within time limits, you need to solve different variety of puzzles to get a nag of these types of questions. Puzzles are good way to exercise your brain. We will publish more such puzzles in future, so stay tuned.
Did you find the article useful? How many questions were you able to solve? How much time did you take to solve each? What do you think of the difficulty level of these puzzles?