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Algebraic Riddle
Brainteaser: Algebraic Riddle
Diophantus was a Greek mathematician who lived in the third century. He was one of the first mathematicians to use algebraic symbols. Most of what is known about Diophantus's life comes from an algebraic riddle from around the early sixth century. The riddle states: Diophantus's youth lasted one sixth of his life. He grew a beard after one twelfth more. After one seventh more of his life, he married. 5 years later, he and his wife had a son. The son lived exactly one half as long as his father, and Diophantus died four years after his son. How many years did Diophantus live?
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Sailer
Brainteaser: Sailer
We are brave sailors always riding the sea We are less than one hundred but as tough as can be We sleep in three bunkers on top of each other Our numbers double from one bunker to another We dance in joy all through the night In groups of fives under the moonlight Last night twelve of us were swallowed by waves Leaving alive more than two third of the braves Still we continue the journey refusing to fail So tell me how many of us are left to sail?
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Coins
Brainteaser: Coins
Imagine, we are sitting together at a perfectly round table. We both have an infinite pile of coins. These are the rules of the game: “We'll take turns putting one coin down on the table, no overlapping allowed, and the coins must rest flat on the table surface. The first guy who can't put a coin down loses." Who should start in order to win, why and how does your strategy work?
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The cube
Brainteaser: The cube
You’ve got a 10 x 10 x 10 cube made up of 1 x 1 x 1 smaller cubes. The outside of the larger cube is completely painted red. On how many of the smaller cubes is there any red paint?
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Brainteasers are a helpful exercise to train your logical thinking.
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True/False Statements
Brainteaser: True/False Statements
There are a hundred statements. First person says: At least one of the statements is false. Second person says: At least two of the statements is false. Third person says: At least three of the statements are false. Fourth person says: At least four of the statements are false. .. .. .. Hundredth person says: At least a hundred of the statements are false. Analyzing it, how many statements do you think are false and how many are right?
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Missing Price
Brainteaser: Missing Price
When I went to the store, I purchased four items. The following shows the cost of three of the items: $1.50 $3.00 $4.00 The line to the checkout was pretty long, so to quench my boredom I started playing with my pocket calculator while waiting. I found out, to my surprise, that the four prices of the four items I purchased added to the same number as I got when I multiplied the four prices together. What was the price of the fourth item?
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The watch
Brainteaser: The watch
The number of girls who do wear a watch is double the number who don't. But the number of boys who do not wear a watch is double the number who do. If I tell you the number of girls in my class is double the number of boys, can you tell me the number I teach? Here's a clue: More than 20, but below 32.
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Number Tricks
Brainteaser: Number Tricks
Ms. Arroyo asked the class to see if they could find the sum of the first 50 odd numbers. As everyone settled down to their addition, Terry ran to her and said, ""The sum is 2,500."" Ms. Arroyo thought, ""Lucky guess,"" and gave him the task of finding the sum of the first 75 odd numbers. Within 20 seconds, Terry was back with the correct answer of 5,625. How does Terry find the sum so quickly?
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Cheryl's birthday
Brainteaser: Cheryl's birthday
Albert and Bernard just become friends with Cheryl, and they want to know when her birthday is. Cheryl gives them a list of 10 possible dates. May 15 May 16 May 19 June 17 June 18 July 14 July 16 August 14 August 15 August 17 Cheryl tells Albert and Bernard separately the month and the day of her birthday respectively. Albert: I don’t know when Cheryl’s birthday is, but I know that Bernard does not know too. Bernard: At first I don’t know when Cheryl’s birthday is, but I know now. Albert. Then I also know when Cheryl’s birthday is. So when is Cheryl’s birthday?
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The Picnic
Brainteaser: The Picnic
Suppose you drive to a picnic spot at 20 mph, then how fast you must go while returning back home on the same route such that your average speed becomes 40 mph?
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Smarties
Brainteaser: Smarties
There are three small porcelain cups on the table in front of you. Each cup is covered with an upper shell, that it is impossible for you to see what is insight. Ona each cup there is a label. On the left cup is written “green Smarties”, the label in the middle says “green and yellow Smarties” and the label on the right says “yellow Smarties”. Unfortunately, none of the inscriptions are right, because the labels got interchanged. You are getting the advice to place the labels in the right order. To solve the problem, you can choose one cup, from which you are allowed to see one Smartie. Which cup do you have to choose, to place the labels correctly?
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Seven digit number
Brainteaser: Seven digit number
Can you find a seven digit number which describes itself? The first digit is the number of zeros in the number. The second digit is the number of ones in the number, etc. For example, in the number 21200, there are 2 zeros, 1 one, 2 twos, 0 threes and 0 fours.
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The Race
Brainteaser: The Race
Bobby and Wilbur decided to take their respective car out of the garage and race. None of them cheated and they both stood at the start time and decided to cover a distance in full throttle. The first to reach the mark was to be declared the winner. Upon reaching the finishing mark, they found out that Bobby's car is 1.2 times faster than Wilbur's. Now, Wilbur had reached the mark about 1 minute and 30 seconds later than Bobby. Bobby's car reached the mark at 60 MPH on average. Can you calculate the distance between the starting mark and the final mark with the help of the given data?
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Liars
Brainteaser: Liars
Lisa and Alex are liars. They both lie on some specific days. Lisa lies on Fridays, Saturdays and Sundays. She speaks truth on all other days. Alex lies on Tuesdays, Wednesdays and Thursdays. He speaks truth on all other days. Can you tell that one day of the week when both of them will say, "Tomorrow, I will lie"?
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Required chairs
Brainteaser: Required chairs
In a family supper, a grandfather, a grandmother, two fathers, two mothers, four children, three grandchildren, one brother, two sisters, two sons, two daughters, one daughter in law, and one mother in law need to sit at a table. There are only seven chairs available at the place. How many more chairs do they have to borrow so that everyone can sit down together for the suppers if everybody requires a separate chair?
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Dr. Hauss mystery
Brainteaser: Dr. Hauss mystery
Dr. Hauss goes shopping with his son. He parks his car at the roadside and crosses the street. His son hangs a bit behind. While running after his dad, he does not take care of the traffic at the crossroad and runs into a car. Dr. Hauss calls the ambulance immediately, which arrives at the place of accident a couple of minutes later. The ambulance men ask the father to follow the ambulance car to St. Hedwig Hospital. Unfortunately he is not able to keep following, but knowing the destination he drives to St. Hedwig Hospital on his own. On their way, the ambulance men find out that the St. Hedwig Hospital is overstaffed and change their destination to St. Joseph Hospital, not being able to inform Dr. Hauss. They arrive at St. Joseph Hospital 15 minutes later. Dr. Hauss is being on duty for 11 hours at the St. Joseph Hospital. When the injured son is getting there, Dr. Hauss asks a colleague to take over the surgery: “I am too nervous, I cannot perform the surgery. He is my son!“ How is that possible?
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Small boat
Brainteaser: Small boat
A man weighing 14 stone and his two sons weighing 7 stone each were stranded on an island. All they had to get off the island was a small boat, but it could only hold 14 stone. How did the man and his sons get off the island?
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Troll cake
Brainteaser: Troll cake
You are on your way to visit your Grandma, who lives at the end of the valley. It's her birthday, and you want to give her the cakes you've made. Between your house and her house, you have to cross 7 bridges, and as it goes in the land of make believe, there is a troll under every bridge! Each troll, quite rightly, insists that you pay a troll toll. Before you can cross their bridge, you have to give them half of the cakes you are carrying, but as they are kind trolls, they each give you back a single cake. How many cakes do you have to leave home with to make sure that you arrive at Grandma's with exactly 2 cakes?
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Balls in a bag
Brainteaser: Balls in a bag
There is a bag with 21 blue balls and 23 red balls. You have another 22 red balls outside the bags. Randomly remove two balls from the bag. * If they are of different color, put the blue one back into the bag. * If they are the same color, take them out and put a red marble back into the bag. Repeat this until only one ball remains in the bag. What is the color of the sole ball left in the bag ?
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Marry the king's daughter
Brainteaser: Marry the king's daughter
A miller asks to marry the king’s daughter. The king makes a deal with the miller and says he will write "Yes," on one card and "No" on another one. The miller will have to draw one card in front of the whole village. The night before the miller was to draw the card he heard that the king was going to write "No" on both cards. How can the miller be sure he gets to marry the king’s daughter?
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Wetter and wetter
Brainteaser: Wetter and wetter
What gets wetter and wetter the more it dries?
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1 2 4 5 6 7 8 10 14 15

Questions

Frequently Asked Questions
We are happy to answer the most frequently asked questions.

Brain teasers in the form of math problems and logic puzzles can still appear in interviews, but they are quite rare. More common now are market sizing guesstimates, such as “How many tennis balls can fit into a smart car?” These questions may also be referred to as brain teasers. In general, brain teasers test your creativity and ability to think outside the box.

Brain teasers are uncommon in interviews, and there is no specific rule regarding when an interviewer may choose to use one. However, they are more typical in final rounds and can be asked either before or after the main case discussion.

Market sizing guesstimates are often referred to as brain teasers as well. They are more common in interviews and consist of questions that ask you to determine a specific quantity, such as “How many golf balls can you fit into a passenger Boeing 747?” These questions test your ability to define a problem, break it down into assumptions, and use math to solve it.

Always prioritize case studies and the personal fit portion in your interview preparation, as these are the crucial aspects of your interview! Once you feel more comfortable with those, you can integrate some brain teaser practice into your preparation. This may give you the advantage you need to stand out among other candidates! You can use our brain teaser library to challenge your creative thinking. Have fun!

Brain Teaser – Challenge Your Logical and Numerical Thinking

A brain teaser is a riddle or puzzle designed to challenge your logical thinking. In interviews, interviewers may use them to gain insights into your logical and creative thinking skills, which are valuable in various careers. The most important aspect here is not just the answer but how you approach the problem. Practice our brain teasers to prepare yourself for any interview situation!

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