Interview Riddles

How Long Was He Walking

Puzzle: Every day, Jack arrives at the train station from work at 5 pm. His wife leaves home in her car to meet him there at exactly 5 pm, and drives him home. One day, Jack gets to the station an hour early, and starts walking home, until his wife meets him on the road. Read More →

Frog and Well Puzzle

Puzzle: A frog is at the bottom of a 30 meter well. Each day he summons enough energy for one 3 meter leap up the well. Exhausted, he then hangs there for the rest of the day. At night, while he is asleep, he slips 2 meters backwards. How many days does it take him Read More →

Cut Painted Cube Puzzle

Cut cube

Puzzle: A solid, four-inch cube of wood is coated with blue paint on all six sides. Then the cube is cut into smaller one-inch cubes. These new one-inch cubes will have either three blue sides, two blue sides, one blue side, or no blue sides. How many of each will there be? Puzzle Solution: Subtract Read More →

5 Pirates Fight for 100 Gold Coins Puzzle

Puzzle: 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 Read More →

3 Baskets And 4 Balls Puzzle

Puzzle: You have 3 baskets and each basket contains exactly 4 balls, each balls is of the same size. Each ball is either red, black, yellow, or orange, and there is one of each color in each basket. If you were blindfolded, and lightly shook each basket so that the balls would be randomly distributed, Read More →

Chasing Dog Puzzle

Puzzle: There are four dogs each at the corner of a unit square. Each of the dogs starts chasing the dog in the clockwise direction. They all run at the same speed and continuously change their direction accordingly so that they are always heading straight towards the other dog. How long does it take for the Read More →

Red and Blue Balls in a Bag

Problem: You have 20 Blue balls and 10 Red balls in a bag. You put your hand in the bag and take off two at a time. If they’re of the same color, you add a Blue ball to the bag. If they’re of different colors, you add a Red ball to the bag. What Read More →

Cashier’s Puzzle


Problem: An engineer goes to a bank with a check of $200 and asks the cashier “Give me some one-dollar bills, ten times as many twos and the balance in fives!”. What will the cashier do? Solution: The smallest amount of one-dollar and two-dollar bills the cashier may give to the old man is 1×1 Read More →

Supersonic bee and trains

Problem: Two trains enter a tunnel 200 miles long, traveling at 100 mph at the same time from opposite directions. As soon as they enter the tunnel a supersonic bee flying at 1000 mph starts from one train and heads toward the other one. As soon as it reaches the other one it turns around Read More →

Probability of finding a job

Problem: A candidate is selected for interview for 3 posts.The number of candidates for the first, second and third posts are 3,4 and 2 respectively. What is the probability of getting at least one post? Solution: The probability the candidate does not get an offer from the first interview is 2/3. The probability she doesn’t Read More →

Age of 3 children – Mathematical Puzzle

Problem: Two old friends, Jack and Bill, meet after a long time. Jack: Hey, how are you man? Bill: Not bad, got married and I have three kids now. Jack: That’s awesome. How old are they? Bill: The product of their ages is 72 and the sum of their ages is the same as your Read More →

River Crossing Puzzle

River crossing puzzle

Problem: Sailor Cat needs to bring a wolf, a goat, and a cabbage across the river. The boat is tiny and can only carry one passenger at a time. If he leaves the wolf and the goat alone together, the wolf will eat the goat. If he leaves the goat and the cabbage alone together, Read More →