1.
Introduction
2.
Puzzle Description
3.
Solution
4.
4.1.
Why are puzzles asked in interviews?
4.2.
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?
4.3.
What are some of the important puzzles asked in the interview?
5.
Conclusion
Last Updated: Mar 27, 2024

# Fake Note

Urwashi Priya
0 upvote
Master Python: Predicting weather forecasts
Speaker
Ashwin Goyal
Product Manager @

## Introduction

Puzzles are a really good measure of one's analytical skills and lateral thinking. Many product-based companies ask the puzzles to help them filter candidates based on their real-world problem-solving skills to approach a problem they have not seen before.

A puzzle may have multiple solutions, where the interviewer is generally interested in the candidate's approach to not only solving the puzzle but the approach to building and thinking creatively for the solution to the puzzle.

On the same note, we are going to discuss a very interesting puzzle commonly asked in interviews.

## Puzzle Description

A man named M bought some goods worth Rs. 200 from a shopkeeper named X. The man paid him Rs. 1000. The shopkeeper X took the change from Shopkeeper Y and returned 800 to the man. After a few days, the shopkeeper realised that the 1000 rupees note was fake and he reached out to the man and took the real 1000 note from him.

So in this whole process how much money did the shopkeeper X lose in the end?

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## Solution

Man(M) paid Rs. 1000 to the shopkeeper. He has bought products for only Rs. 200. So the shopkeeper returns him Rs. 800. Now, 1000 paid to the shopkeeper was a fake note. Hence, he gets his 1000 back from the man. So, the shopkeeper suffered no loss as the fake amount which he received was all returned to him.

Check out this problem - Check If A String Is Palindrome

### Why are puzzles asked in interviews?

Puzzles are asked in interviews to check for the analytical and lateral reasoning ability of students. It also involves the problem-solving skills of the students.

### 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?

First, we have to conduct 5 races taking 5 horses each, then we need to convert another 1 race for all winners. This race decides the top 3 horses.

### What are some of the important puzzles asked in the interview?

Some puzzles asked in the interview are: Ant and Triangle Problem, Crossing the Bridge Puzzle, Burning Rope Problem, Bag of Coins Puzzle, Horses on a Race Track Puzzle.

## Conclusion

We hope you could easily take away all critical and conceptual techniques by walking over the given examples.

Now, we strongly recommend you to understand the other related concepts in puzzles and enhance your learning. You can get a wide range of topics similar to this on the interview puzzle.
You can refer to our Guided Path on Coding Ninjas Studio to upskill yourself in Data Structures and AlgorithmsCompetitive ProgrammingJavaScriptSQLSystem Design, and many more!

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