Puzzles are often used in interviews to assess a candidate's problem-solving, analytical thinking, and logical reasoning skills. These 25 puzzles include famous and commonly asked ones, providing a comprehensive collection to prepare for various interview scenarios.
| No. | Puzzle | Description |
|---|---|---|
| 1 | The River Crossing Puzzle | A farmer needs to transport a wolf, a goat, and a cabbage across a river. He has a boat that can carry only him and one other item at a time. How can he do it without leaving the wolf alone with the goat or the goat alone with the cabbage? |
| 2 | The Two Jug Problem | You have a 3-liter jug and a 5-liter jug. How can you measure exactly 4 liters of water using these two jugs? |
| 3 | The Missing Dollar Riddle | Three people check into a hotel room that costs $30. They each contribute $10. Later, the hotel realizes the room was only $25 and gives $5 back. The bellboy can't split the $5 evenly, so he gives $1 to each person and keeps $2 for himself. Each person paid $9, totaling $27. Adding the $2 kept by the bellboy makes $29. Where is the missing dollar? |
| 4 | The Light Switch Puzzle | You are in a room with three light switches that correspond to three light bulbs in another room. You can only go into the other room once. How do you determine which switch corresponds to which bulb? |
| 5 | The Coin Weighing Puzzle | You have 12 coins, and one of them is fake (heavier or lighter). You have a balance scale and can use it three times. How do you identify the fake coin? |
| 6 | The Chessboard Puzzle | You have a standard 8x8 chessboard with two diagonally opposite corners removed. Can you cover the remaining board with 31 dominoes (each covering two squares)? |
| 7 | The Frog and the Well | A frog is at the bottom of a 20-meter well. It can jump 3 meters up but slides back 2 meters after each jump. How many jumps does it take for the frog to reach the top? |
| 8 | The Monty Hall Problem | You're on a game show with three doors: behind one is a car, and behind the others are goats. You choose a door, and the host, who knows what's behind the doors, opens another door revealing a goat. You are then given a chance to switch your choice. Should you switch, and why? |
| 9 | The Birthday Paradox | In a room of 23 people, what is the probability that at least two people share the same birthday? |
| 10 | The Crossing Bridge Puzzle | Four people need to cross a bridge at night with one flashlight. They can only cross two at a time, and they take 1, 2, 5, and 10 minutes respectively to cross. When two people cross, they must go at the slower person's pace. How do they all get across in 17 minutes? |
| 11 | The Three Switches Puzzle | You are in a room with three switches. One of the switches controls a light bulb in another room. You can only check the bulb once. How can you determine which switch controls the bulb? |
| 12 | The Camel and Bananas Puzzle | A camel must transport 3000 bananas across a 1000-mile desert. The camel can carry a maximum of 1000 bananas at a time and eats one banana every mile it walks. What is the maximum number of bananas the camel can transport across the desert? |
| 13 | The Handshake Puzzle | At a party, everyone shook hands with everybody else. There were 66 handshakes. How many people were at the party? |
| 14 | The Hourglass Puzzle | You have a 4-minute hourglass and a 7-minute hourglass. How can you measure exactly 9 minutes? |
| 15 | The Apple Basket Puzzle | You have 10 baskets, each with 10 apples. Each apple weighs 1 kg, except one basket where each apple weighs 0.9 kg. How do you find the basket with the lighter apples using a digital scale only once? |
| 16 | The Egg Drop Puzzle | You have two identical eggs and access to a 100-story building. The eggs break if dropped from a certain floor and above. How do you find the highest floor from which you can drop an egg without breaking it, using the fewest drops? |
| 17 | The Wolf, Goat, and Cabbage Puzzle | A farmer needs to get a wolf, a goat, and a cabbage across a river. He has a boat that can carry only him and one other item at a time. How does he do it without leaving the wolf alone with the goat or the goat alone with the cabbage? |
| 18 | The Rope Burning Puzzle | You have two ropes and a lighter. Each rope takes exactly one hour to burn, but they do not burn at a constant rate. How do you measure exactly 45 minutes? |
| 19 | The Manhole Cover Puzzle | Why are manhole covers round? |
| 20 | The Chicken and Egg Problem | Which came first, the chicken or the egg? |
| 21 | The Fish Weighing Puzzle | You have a fish that weighs 12 grams plus half of its own weight. How much does the fish weigh? |
| 22 | The Two Sons Riddle | A man is looking at a picture of someone. His friend asks, "Who is it you are looking at?" The man replies, "Brothers and sisters I have none, but that man's father is my father's son." Who is in the picture? |
| 23 | The Frog and Stones Puzzle | There are 10 stones in a row. A frog can jump over one or two stones. How many different ways can the frog reach the 10th stone? |
| 24 | The Light Bulbs in a Row Puzzle | You have 100 light bulbs in a row, all initially turned off. You toggle every second bulb, then every third bulb, and so on until you toggle the 100th bulb. How many bulbs are left on? |
| 25 | The Farmer and the Three Sons Puzzle | A farmer wants to divide his 17 horses among his three sons. He wants to give half to the first son, one-third to the second son, and one-ninth to the third son. How does he do it without cutting any horses? |
FAQs about Puzzles
- Why do interviewers use puzzles during interviews?
- Interviewers use puzzles to assess a candidate's problem-solving skills, logical thinking, creativity, and ability to handle complex situations. Puzzles also help evaluate how candidates approach and break down problems.
- How should I approach solving an interview puzzle?
- Understand the problem clearly, break it down into smaller parts, think aloud to show your thought process, consider different approaches, and explain your reasoning step by step.
- What if I can't solve the puzzle during the interview?
- It's important to remain calm and show your problem-solving process. Even if you don't reach the correct answer, demonstrating your logical approach and reasoning can still leave a positive impression.
- Are there common types of puzzles frequently asked in interviews?
- Yes, common types include logic puzzles, mathematical problems, probability puzzles, and riddles. Familiarizing yourself with these types can help you prepare better.
- How can I prepare for puzzle interviews?
- Practice solving a variety of puzzles, study common types of interview puzzles, work on your logical and analytical thinking skills, and participate in mock interviews to get comfortable with the format.
- Do puzzle-solving skills translate to real job skills?
- Yes, puzzle-solving skills are closely related to problem-solving and analytical skills required in many job roles. The ability to think logically, approach problems methodically, and find creative solutions is highly valuable in the workplace.
- What resources can I use to practice puzzle-solving?
- Online puzzle websites, puzzle books, mobile apps, and interview preparation platforms offer a wide range of puzzles to practice. Joining puzzle-solving communities and forums can also provide valuable practice and insights.
- How important is it to find the correct answer to a puzzle in an interview?
- While finding the correct answer is important, interviewers are often more interested in your problem-solving approach and logical reasoning. Showing a structured and methodical approach can be as valuable as finding the correct solution.
- Can discussing puzzles with peers help in preparation?
- Absolutely. Discussing puzzles with peers can provide different perspectives, improve your problem-solving techniques, and help you learn new strategies. It also makes the preparation process more engaging and enjoyable.
- Are there any specific industries or roles where puzzle interviews are more common?
* Puzzle interviews are particularly common in tech roles, such as software development, data science, and engineering. However, they can also be used in consulting, finance, and other analytical roles to assess problem-solving abilities.
