Curated Video
The HARDEST Logic Puzzle Ever (Simpler Version): Two Doors To Freedom Riddle
An evil warden holds you prisoner, but offers you a chance to escape. 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...
Curated Video
"UNSOLVABLE" Logic Puzzle: What Are Their Ages?
This is one of those brain teasers that sounds like it's impossible to solve but you can work through it (like the logic puzzle of Cheryl's birthday). A mathematician tells a census taker he has 3 children. The product of their ages is...
Curated Video
"Impossible" Logic Puzzle - How Many Liars Are At The Party?
A party has 100 people who are either liars are truth tellers. Liars always lie and truth tellers always say the truth. After the party you ask each person, "How many truth tellers did you shake hands with?" Each person gives a different...
Gresham College
Logical Puzzles
A quick introduction to some logical puzzles. Robin Wilson, Gresham Professor of Geometry, runs through some sample problems, from Epimenides to Lewis Carroll. This is the twelth part of 'A Millennium of Mathematical Puzzles'. The full...
Curated Video
Can You Solve The Rabbit Race Logic Puzzle?
How can 10 rabbits plan races so each rabbit "beats" every other rabbit in some race? What if there are n rabbits? My blog post for this video: https://wp.me/p6aMk-55O Source I received this problem by email from Stephan who translated...
Curated Video
Can You Solve The "IMPOSSIBLE" Handshake Logic Puzzle?
Mr. Lars and his wife Mrs. Lars went to a meetup and met 4 other married couples. Some people shook hands with each other, but no person shook hands with his or her spouse, and no person shook his or her own hand. Mr. Lars then asked...
Curated Video
The Seemingly IMPOSSIBLE Guess The Number Logic Puzzle
Alice and Bob are secretly told consecutive numbers, but neither knows the other person's number. They cannot communicate or plan a strategy in advance. They get $1 million each if one of them can guess the other's number correctly. The...
Curated Video
MIND-BENDING LOGIC PUZZLE - The Self-Counting Sentence
"In this sentence, the number of occurrences of the digit 0 is __, of the digit 1 is __, of the digit 2 is __, of the digit 3 is __, of the digit 4 is __, of the digit 5 is __, of the digit 6 is __, of the digit 7 is __, of the digit 8...
Curated Video
The Seemingly Impossible Escape Logic Puzzle
An evil logician takes Alice and Bob captive. They have a chance to escape if they can deduce the total number of trees in the prison. Can they figure it out? Source of puzzle wu: riddles forum...
Curated Video
HARD Logic Puzzle: How Can Spies Share Secrets Efficiently?
After a successful mission, each of N spies obtains a unique secret. By protocol, the spies share secrets by a series of phone calls between 2 spies at a time. During a call, a spy can share all the secrets the knows, including secrets...
Curated Video
Teresas Daughter Is My Daughter's Mother - Viral Facebook Logic Puzzle
This problem already has over 175,000 shares on Facebook. Can you solve it? "If Teresa's daughter is my daughter's mother, then what is my relationship to Teresa?" a. her grandmother b. her mother c. her daughter d. her granddaughter e....
Curated Video
HARD Logic Puzzle - The Seemingly Impossible Counterfeit Coin Problem
An evil warden holds you prisoner, but offers you a chance to earn your freedom. You are given 101 coins, of which 51 are genuine and 50 are counterfeit. Each genuine coin is identical. And each counterfeit coin is identical to a genuine...
Curated Video
HOW SMART ARE YOU? 80% FAIL The Dance Club Line Logic Riddle
There is a long single-file line outside of a dance club. The first person in line is unmarried, and the last person in line is married. Each person in line only looks at the person in front of them. Is a married person looking at an...
Curated Video
Can You Solve The Lying Fishermen Riddle? A Fantastic Algebra Puzzle
Thanks to Halvor Kjærås for creating this logic puzzle! Barney says he caught 5 fish, and Alfred says he caught 2. But each person fibs about numbers when spoken aloud. Can you figure out how many each person actually caught? My blog...
Curated Video
Circle Theorems - Part 1 | Geometry & Measures | Maths | FuseSchool
CREDITS Animation & Design: Murray Knox Narration: Lucy Billings Script: Lucy Billings In these 3 videos we are going to discover 9 different circle theorems. I’m a big fan of them - they’re like little logic puzzles. Before we get...
Curated Video
VERY HARD South Korean Geometry Problem (CSAT Exam)
Thanks to Hyeong-jun (H. J.) for emailing me this problem! This is a challenging problem from the math section of the 1997 CSAT, a standardized test in South Korea. Can you figure it out? It took me several attempts, but it was really...
Curated Video
Can You Solve The Hardest Easy Geometry Problem?
In the figure, what is the value of angle x? This problem is known as Langley's Adventitious Angles. It is also known as the hardest easy geometry problem because it can be solved by elementary methods but it is notoriously difficult to...
Curated Video
A 16 Year Old Discovered This AMAZING Geometry Hidden Pattern. Pascal's Theorem
Pascal discovered this amazing geometry result when he was only 16. The book "The Art of the Infinite" by Robert Kaplan and Ellen Kaplan has a wonderful introduction to projective geometry and a proof this this theorem. Proof of Pascal's...
Curated Video
Seemingly Impossible Puzzle - Who Lost The 4th Game?
Thanks to Omer from Israel for suggesting this type of puzzle! Three friends rotate playing 1-on-1 basketball games. If A played 8 games, B played 11 games, and C played 15 games, who lost the 4th game? It seems impossible but you can...
Curated Video
Can You Solve The Marriage Logic Problem? 80% Fail
Surveys have found 80 percent get this logic problem wrong. Alice is looking at Bob, and Bob is looking at Charlie. Alice is married; Charlie is not. Is a married person looking at an unmarried person? Answer choices are A) Yes, B) No,...
Curated Video
Can You Solve This MIT Admissions Question? Geometry Problem, 1869
The Massachusetts Institute of Technology (MIT) is one of the top ranked universities in the world. This question appeared on its admissions exam nearly 150 years ago. "The perpendicular dropped from the vertex of the right angle upon...
Curated Video
Solution to The Marble Color Puzzle
Watch the puzzle video first: https://www.youtube.com/watch?v=XdT6cXH5YdQ This problem appears in my book "40 Paradoxes in Logic, Probability, and Game Theory" (5 stars on Amazon): http://amzn.to/192boRJ This problem is known as...
Curated Video
Can You Solve The Viral 9 = 72 Puzzle? The Correct Answer Explained
This problem has been shared millions of times on Twitter/Facebook with the claim "99% fail" to solve it and that only a genius could find the correct answer. If 9 = 72, 8 = 56, 7 = 42, 6 = 30, 5 = 20, then 3 = ? In this video I explain...
Curated Video
When Is Cheryl's Birthday? Answer To Viral Math Puzzle
This problem went viral after it appeared on a Math Olympiad test for talented students in Singapore. It's not a trick question! Here's the problem, which I have very slightly re-worded for clarity. Blog post (detailed text explanation):...