background preloader

Logic Puzzles

Facebook Twitter

The Seemingly Impossible Guess The Number Logic Puzzle – Mind Your Decisions. Long time readers may recognize this previously posted problem as will people who have read my book Math Puzzles Volume 1.

The Seemingly Impossible Guess The Number Logic Puzzle – Mind Your Decisions

Alice and Bob are on a game show. Each is secretly told a whole, positive number. They are told the two numbers are consecutive, but neither knows the other person’s number. For example, if Alice is told 20, she does not know if Bob was told 19 or 21. And if Bob is told 21, he does not know if Alice was told 20 or 22. –Alice and Bob cannot communicate with each other, and they are not allowed to plan their strategy either. Can you solve it? Are you in the smartest 10 per cent? Hello guzzlers, Today’s puzzle is about a rod and a string.

Can you solve it? Are you in the smartest 10 per cent?

A string is wound symmetrically around a circular rod. The string goes exactly four times around the rod. The circumference of the rod is 4cm and its length is 12cm. Find the length of the string. This question was originally set twenty years ago in an exam given to 18-year-olds in 16 countries studying ‘advanced’ maths. It was one of the most difficult questions in the test, with only 10 per cent of students overall getting the right answer. The problem, however, is rather beautiful. I’ll be back at 5pm GMT with the answer.

My book Football School, co-written with Ben Lyttleton, is just out in paperback. Can You Solve The 25 Horses Puzzle? Google Interview Question – Mind Your Decisions. Here is a problem that has been asked as an interview question.

Can You Solve The 25 Horses Puzzle? Google Interview Question – Mind Your Decisions

There are 25 horses. What is the minimum number of races needed so you can identify the fastest 3 horses? You can race up to 5 horses at a time, but you do not have a watch. As this question is a bit vague, here is a more precise version you can solve. Interview Question (with more details) There are 25 mechanical horses and a single racetrack. I was suggested this problem by email from puzzle maker and speaker Terry Stickels. This is also a classic interview question asked during programming interviews at tech companies like Google. The Two Doors To Freedom Logic Problem. Sunday Puzzle – Mind Your Decisions. You are a prisoner in logicland, and the warden offers you a chance to escape.

The Two Doors To Freedom Logic Problem. Sunday Puzzle – Mind Your Decisions

There are 3 doors A, B, and C. Two of the doors lead to freedom and the third door leads to lifetime imprisonment, but you do not which door is what type. You are allowed to point to a door and ask a single yes-no question to the warden. If you point to a door that leads to freedom, the warden does answer your question truthfully. But if you point to the door that leads to imprisonment, the warden answers your question randomly, either saying “yes” or “no” by chance. The Bananas, Clock, Hexagon Viral Logic Puzzle – Mind Your Decisions. This problem is being shared with claims that only geniuses can solve it and that 99 percent fail to find the correct answer.

The Bananas, Clock, Hexagon Viral Logic Puzzle – Mind Your Decisions

Can you figure it out? Watch the video for a solution. Viral Problem – Can You Solve The Bananas, Clock, Hexagon Puzzle? When Is Cheryl’s Birthday? Answer To Viral Math Puzzle – Mind Your Decisions. This problem appeared on a Math Olympiad question for high school students in Singapore.

When Is Cheryl’s Birthday? Answer To Viral Math Puzzle – Mind Your Decisions

After it was posted to Facebook, the problem went viral generating debate about the correct answer. Video Version I’ve posted the problem and explained the answer on my YouTube channel. When is Cheryl’s Birthday? How Many Liars Are At The Party? Sunday Puzzle – Mind Your Decisions. At a party there are 100 people who are either liars or truth tellers.

How Many Liars Are At The Party? Sunday Puzzle – Mind Your Decisions

Liars always lie and truth tellers always speak the truth, and each person can identify the type of others. After the party is over, you ask each person, “How many truth tellers did you shake hands with?” Each person gave a different whole number answer from 0 to 99 (the answers were 0, 1, 2, …, 98, 99). The Seemingly Impossible Escape – Sunday Puzzle – Mind Your Decisions. Here is a logic puzzle that depends on the game theory concept of common knowledge.

The Seemingly Impossible Escape – Sunday Puzzle – Mind Your Decisions

Can you figure it out? Alice and Bob are taken prisoners by an evil logician. They are given one chance to be set free. Alice and Bob are placed in cells that have a view of a courtyard with trees. There are 20 trees in all, of which Alice sees 12 and Bob sees 8. Neither prisoner knows how many trees the other sees. They have to figure out the total number of trees, but they are not allowed to communicate with each other.

Each day the logician visits Alice in her cell and asks, “Are there 18 or 20 trees in total?” Alice has two choices: she can guess or pass. Blog-post_20. Finder. Brain Food. Printable Logic Puzzles. Printable Logic Puzzles Logic puzzles (also known as "logic grid puzzles") require the solver to deduce the relationships between different people, places and things based on a limited number of clues given in the puzzle.

Printable Logic Puzzles

Remember: every item on the board belongs to one and only one person, no item will ever be shared. Using only the clues provided and simple deductive logic and reasoning, fill in the grid with X's and O's to determine the solution. Two easy and challenging printable logic puzzles will be made available every day, directly from this page. 4x6 and 4x7 puzzles are each published once per week, on Fridays and Tuesdays. If you can't wait until tomorrow for your next logic puzzle fix, check out Logic-Puzzles.org and solve more than 10,000 unique logic puzzles online. Easy 4x4 Logic Puzzles Our 4x4 puzzles are a perfect introduction to those new to logic puzzles, or to seasoned solvers who want a quick puzzle-fix. Logic Puzzles - Play Online or Print Your Own for Free!