The field of data analytics is witnessing an immense development in this Internet era. If this attracts you, then it is mandatory to shine in certain parameters. They are extensive use of statistics, data handling tool and most importantly the problem solving technics. The number crunching skill and the structured thinking capacity are seen are the key capability of any data analytical officer.

The top three types of questions framed in a professional Data Analytics interview are – Puzzles, Business Case Study, and Guess Estimate. Let’s look at the top 5 Data Analytics queries that are put forward in the interviews:

Puzzle 1:

Two trains X and Y (80 km from each other) are running towards each other on the same track at the speed of 40 kmph. A bird starts from the train X and travel towards train Y with the average speed of 100 kmph. Once it reached train Y, it is directed back towards train X. This happens until the two trains collide. Find the total distance travelled by the bird?

The time given to solve this puzzle is 1 minute.

The main motto of the question is analyze the smart and short cut technics used by the interviewee.

What is the solution?

Velocity of two trains = (40 40) kmph

Time trains will take to collide = 80kmph/80kmph = 1 hour

Distance travelled by bird = 100 kmph * 1 hr = 100 km.

Puzzle 2:

There are 5 lanes on a race track. One has to find out the 3 fastest horses among the 25. Find out the minimum number of races to be conducted in order to determine the fastest three.

The time given to solve this puzzle is 1 minute.

The main motto of the question is analyze interviewee’s approach to solve problems.

What is the solution?

There are 5 races where each group would involve 5 horses. In a tied position, a sixth race is conducted between the first 5 races to determine the fastest 3 (marked A1, B1, A=and C1). The seventh race is conducted between horses B1, C1, second and third horse from the horse A1’s group (A2, A3), second horse from horse B1’s group (B2). The horses that finish 1st and 2nd in the seventh race, are actually the 2nd and the 3rd fastest horses among all horses.

Puzzle 3:

There are 3 mislabeled jars, with apple and oranges in the first and second jar respectively. The third jar contains a mixture of apples and oranges. You can pick as many fruits as required to precisely label each jar. Determine the minimum number of fruits to be picked up in the process of labeling the jars.

A noticeable aspect in this puzzles is the fact that there’s a circular misplacement, which implies if apple is wrongly labelled as Apple, Apple can’t be labelled as Orange, i.e., it has to be labeled as A O. We are acquainted with the fact that everything is wrongly placed, which means A O jar contains either Apple or Orange (but not both). The candidate picks one fruit from A O, and let’s assume he gets an apple. He labels the jar as apple, however, jar labelled Apple can’t have A O. Thus, the third jar left in the process should be labelled A O. Basically, picking only one fruit helps in correctly labeling the jars.

Puzzle 4:

You have two sand timers, which can show 4 minutes and 7 minutes respectively. Use both the sand timers (at a time or one after other or any other combination) and measure a time of 9 minutes.

What is the solution?

1. Start the 7 minute sand timer and the 4 minute sand timer.
2. Once the 4 minute sand timer ends turn it upside down instantly.
3. Once the 7 minute sand timer ends turn it upside down instantly.
4. After the 4 minute sand timer ends turn the 7 minute sand timer upside down(it has now minute of sand in it)

So effectively 8 1 = 9.

Puzzle 5:

N persons are standing in a circle. They are labelled from 1 to N in clockwise order. Every one of them is holding a gun and can shoot a person on his left. Starting from person 1, they starts shooting in order e.g for N=100, person 1 shoots person 2, then person 3 shoots person 4, then person 5 shoots person 6… then person 99 shoots person 100, then person 1 shoots person 3, then person 5 shoots person 7 and it continues till all are dead except one. What’s the index of that last person?

What is the solution?

Write 100 in binary, which is 1100100 and take the complement which is 11011 and it is 27. Subtract the complement from the original number. So 100 – 27 = 73.

Try it out for 50 people. 50 = 110010 in binary.

Complement is 1101 = 13. Therefore, 50 – 13 = 37.

For the number in form 2^n, it will be the first person. Let’s take an example:

64 = 1000000

Complement = 111111 = 63.

64-63 = 1.

You can apply this for any ’n’.

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