Search Results: "Rationality"

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10:34 Popular
Behavioral Economics: Crash Course Econ 27

726 views / 1 likes - added 8 years ago

Why do people buy the stuff they buy? In classical economics, most models assume that consumers behave rationally. As you've probably noticed in your real life, in case after case, people don't actually make rational decisions. There can be emotional or s
03:28 Popular
Flower Math Problem - Adults Stumped By Question For Kids In China

1,379 views / 2 likes - added 7 years ago

This problem is said to come from a test given to a Chinese kindergarten class (5 year olds). It was posted online and caused a lot of debate as adults were stumped about the correct answer, some saying it is impossible. Can you figure it out? This video
04:13 Popular
Adults Stumped By Geometry Problems For 10 Year Olds. Can You Solve Them?

833 views / 0 likes - added 7 years ago

These homework problems were given to 10 year old children (Year 5) in England (Glossop, Derbyshire) and they were posted to Facebook when some adults found them to be difficult. One person claimed the problems were impossible to solve. Can you figure the
02:37 Popular
Adults Stumped By Maths Questions For 15 Year Olds. Can You Solve Them?

785 views / 0 likes - added 7 years ago

How hard are math tests? A survey asked 2,000 UK adults to answer sample GCSE test questions intended for 15 year old students. On average, the survey questions were missed by about 40% of adults. Can you solve them? The video presents 2 questions that ma
05:09 Popular
Can You Solve The Snake Eyes Probability Riddle?

831 views / 0 likes - added 7 years ago

You close your eyes and roll a pair of dice. The casino dealer announces that at least one of the rolls is showing a 1.What is the probability that both dice are showing a 1? Watch the video for the solution. (Snake eyes is a term for rolling a pair of 1s
03:09
Can You Solve The Marriage Logic Problem? 80% Fail

666 views / 0 likes - added 7 years ago

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, and C) Cannot be de
02:57 Popular
Can You Solve This Crazy Equation? Ramanujan's Radical Brain Teaser

1,081 views / 0 likes - added 7 years ago

In 1911, Srinivasa Ramanujan posed this problem involving an infinite nested radical (a never-ending expression that has square roots inside of square roots). Can you figure out how to simplify the equation? The video presents an intuitive solution. Techn
08:27
Can You Solve The 3 Cards Riddle?

670 views / 0 likes - added 7 years ago

There are 3 cards in this problem. One card is blue on both sides, another is red on both sides, and the last is red on one side and blue on the other. The cards are put in a bag and I pick one at random. Without looking at the colors on the card, I place
04:52 Popular
Can You Solve The Two Rope Puzzle?

701 views / 0 likes - added 7 years ago

You have two ropes and a lighter. Each rope burns in 60 minutes, but the ropes do not burn at a constant rate. How can you measure 45 minutes by burning the ropes? Some of you might have heard this problem before. If so, try this variation: how can you me
03:33 Popular
Can You Solve This Intelligence Test? Viral Facebook Puzzle

727 views / 0 likes - added 7 years ago

If 6 + 4 = 210, and 9 + 2 = 711, what is the rule to combine numbers? This "intelligence test" has been shared more than 3 million times on Facebook. On Twitter people claim solving it means you have an IQ of more than 150 (genius level). In this video I
01:57 Popular
I Will Read Your Mind - Math Magic Trick

1,241 views / 2 likes - added 7 years ago

Pick a 2 digit number. Got it? Now and add up the digits. Subtract that from your original number. Look up the resulting number in the table. Can I figure out the symbol you are looking at? This video predicts your symbol and explains why this math trick
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07:52 Popular
Find The 10 Digit Number Classic Puzzle And Solution

873 views / 0 likes - added 7 years ago

I'm thinking of a 10 digit number that uses the each digit 0 to 9 exactly once and where the number formed by the first n digits is divisible by n. What could my number be? The video explains how to find the answer using tests for divisibility. Blog post:
01:18 Popular
Can You Make 4 Triangles From 6 Matches?

967 views / 0 likes - added 7 years ago

Can you use 6 matches to make 4 triangles of equal size and equal shape? This is harder than it sounds! Give it a try before watching the video for a solution. If you like my videos, you can support me at Patreon: http://www.patreon.com/mindyourdecisions
06:24 Popular
The Seemingly Impossible Escape Logic Puzzle

1,433 views / 0 likes - added 7 years ago

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 https://www.ocf.berkeley.edu/~wwu/cgi-bin/yabb/YaBB.cgi?board
02:57 Popular
Viral Facebook Math Problem

1,275 views / 1 likes - added 7 years ago

This problem has over 2 million comments on Facebook and is getting coverage in mainstream media and blogs. Can you figure out this Facebook fruit algebra puzzle involving apples, bananas, and coconuts? The video presents what many people consider to be t
03:25 Popular
Can You Solve This? AA + BB + CC = ABC

2,452 views / 0 likes - added 7 years ago

If AA + BB + CC = ABC, what are the values of A, B, and C? All the digits are distinct and positive. Watch the video for a solution. Blog (text explanation): http://wp.me/p6aMk-4Cm If you like my videos, you can support me at Patreon: http://www.patreon.c
02:23
This SAT Math Question Has A Mistake

649 views / 0 likes - added 7 years ago

This question appeared on the October 1980 SAT exam. Like all questions, it was supposed to have exactly one correct answer. However the test-makers made a mistake. Can you figure out what they did wrong? Blog post (text explanation): http://wp.me/p6aMk-4
04:22 Popular
Impossible Algebra Problem

1,229 views / 0 likes - added 7 years ago

This problem is making the rounds. Can you place numbers in the four boxes so all the equations are true? Blog post (text/image explanation): http://wp.me/p6aMk-4up If you like my videos, you can support me at Patreon: http://www.patreon.com/mindyourdecis
03:31 Popular
How Logical Are You? The Irrationality Illusion Tricks Most

797 views / 0 likes - added 7 years ago

This video relates a cognitive bias ("irrational" decision) to an optical illusion (picture at 1:45). For more, check out my new book, "The Irrationality Illusion: How to Make Smart Decisions And Overcome Bias" http://amzn.to/1o3FaAg Blog post (text and i
01:49 Popular
This Matchstick Puzzle Is

840 views / 1 likes - added 7 years ago

This classic matchstick/toothpick puzzle is making the rounds because it is supposedly "extremely hard" for adults. Can you make 3 squares by moving 3 matchsticks? You cannot break any of the sticks, the resulting squares must be of equal size, and each t
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05:26
Can You Solve The Red Ball Lottery Puzzle?

663 views / 0 likes - added 7 years ago

(Same video without the music: https://youtu.be/sz5oLEpc8xE) This problem involves 100 red balls, 100 blue balls, and 2 urns. First you distribute all the balls between the 2 urns, placing at least 1 ball in each urn. Next, you select an urn at random, an
07:21 Popular
Can You Solve The Magical Pond Puzzle?

1,018 views / 1 likes - added 7 years ago

(Same video with music: https://youtu.be/nF-Gpk0ZpRk) You visit a shrine that has 3 temples. Before each temple, you have to swim in a magical pond. Your path is pond-temple1-pond-temple2-pond-temple 3. Each time you swim, the pond magically triples the n
06:24 Popular
Can You Solve The Chameleon Riddle?

986 views / 0 likes - added 7 years ago

A museum has 13 blue, 15 red, and 17 green chameleons. Whenever two chameleons of different colors meet, they both change into the color of the other chameleon (if blue and red met, for example, they would both turn green). As the chameleons mingle, is it
09:50 Popular
Can You Solve This 6th Grade Geometry Problem From China?

1,253 views / 1 likes - added 7 years ago

What is the total area of the red spots? The diagram involves a rectangle with dimensions of 10 and 20. Inside the rectangle one of its diagonals is connected. There are two circles of equal size that are tangent to each other and the rectangle. The video
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10:20 Popular
SURPRISING Coin Flipping Probability - Flips To HH Versus HT

868 views / 0 likes - added 7 years ago

What is the expected number of coin flips until you get two heads in a row (HH)? What is the expected number of coin flips until you get a heads followed by a tails (HT)? The video presents the solution and an intuitive explanation for this probability ri
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Can You Solve The Friendship Riddle?

537 views / 0 likes - added 7 years ago

In a group of 6 people, you might find that some people are friends on Facebook, or you might find out that no one is friends on Facebook. Show that there is always a group of 3 people in which either: (a) all 3 people are mutual friends or (b) the 3 peop
06:01 Popular
Can You Solve The Viral 1 + 4 = 5 Puzzle? The Correct Answer Explained

11.7k views / 1 likes - added 7 years ago

This problem was shared on Facebook with the claim that only one in a thousand could figure it out. It went viral and generated over 3 million comments. Here is the problem. If 1 + 4 = 5, 2 + 5 = 12, 3 + 6 = 21, what is 8 + 11 = ? This video presents what
05:55 Popular
"Impossible" Logic Puzzle - How Many Liars Are At The Party?

796 views / 0 likes - added 7 years ago

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 answer from 0 to
08:05 Popular
Can You Solve The Hardest Easy Geometry Problem?

1,255 views / 1 likes - added 7 years ago

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 work out. Can you
07:25 Popular
Can You Solve The Race To December 31 Riddle?

705 views / 0 likes - added 7 years ago

Here's a fun game you can play with another person. The game starts on January 1. Each of two players takes turns calling out another date. The new date has to be a later date in the year with either the same month OR the same day (from January 1, a playe
05:33 Popular
What is 6÷2(1+2) = ? The Correct Answer Explained

872 views / 0 likes - added 7 years ago

What is 6÷2(1+2) = ? This problem went viral and generated millions of comments on Facebook, Twitter, YouTube and social media sites. I explain how to get the correct answer by using the modern interpretation of the order of operations. I also explain how
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02:51 Popular
The Horse Horseshoe Boots Viral Algebra Problem - The Correct Answer Explained

1,710 views / 2 likes - added 7 years ago

A lot of people are arguing over the correct answer to this algebra problem involving horses, horseshoes, and boots. A Facebook post with this problem has over 500,000 comments. Can you figure it out? In this video I explain the correct answer. Blog post:
02:06 Popular
Can You Solve The Viral Matchstick Puzzle 6 + 4 = 4?

3,447 views / 0 likes - added 7 years ago

Can you fix 6 + 4 = 4 by moving 1 matchstick? This problem has gone viral on Facebook, with one post having over 400,000 shares. The ground rules are you cannot break a stick, it should be an equality (=), and you have to use 7-segment numbers (the block
11:27 Popular
Can You Solve The Viral 11x11 = 4 Puzzle? The Correct Answer Explained

3,035 views / 1 likes - added 7 years ago

If 11x11=4 and 22x22=16, what is 33x33=? This puzzle has been shared with the claim that only geniuses can solve it. It has gotten millions of views on the internet and Facebook as people have debated the correct answer. In this video I present what many
07:39 Popular
Can You Solve The Alien Extinction Riddle? Hard Job Interview Question

857 views / 0 likes - added 7 years ago

A single alien lands on Earth. Every day after that, each alien on Earth undergoes a transformation, which could be any of the four equally likely events: (a) the alien dies, (b) the alien does nothing, (c) the alien replicates itself (2 aliens total), (d
11:57
The Wallis Formula For π

578 views / 0 likes - added 7 years ago

Start with the pair of fractions (2/1)(2/3). Now increment each number by 2 to get the pair of fractions (4/3)(4/5). Repeat this to get the next pair, and repeat this infinitely many times. If you then multiply all the fractions, you get a marvelous value
07:40 Popular
Can You Solve The 21 Flags Game From Survivor?

874 views / 1 likes - added 7 years ago

Contestants on the TV show "Survivor" faced off in a series of challenges for a grand prize of $1 million. Most of the challenges were physical like hiking many miles or diving underwater. But one challenge was mathematical. The game had 21 flags and cont
05:57 Popular
Can You Solve This 6th Grade Geometry Problem From Singapore? The Area Of A "Claw"

1,116 views / 1 likes - added 7 years ago

This problem was given to Primary 6 (age 11-12) students in Singapore. What is the area of the shaded region in the video, which consists of the region bounded by 4 quarter circles in a 3x3 grid of squares, and each square has a side length of 4? The shad
03:48 Popular
Can You Solve This Harvard Admissions Question? Algebra Problem, 1869

1,443 views / 0 likes - added 7 years ago

The Harvard admissions exam in 1869 included this algebra problem: "A man bought a watch, a chain, and a locket for $216. The watch and locket together cost three times as much as the chain, and the chain and locket together cost half as much as the watch
03:54 Popular
What's The Best Soup Can Size? The Optimal Cylinder Puzzle

785 views / 0 likes - added 7 years ago

A cylindrical can with volume V can be made in different ways. The cylinder can be wide and short (large radius and small height), or it can be narrower and taller (small radius and larger height). Which shape uses the least material? That is, which can h
07:47 Popular
Can You Solve The Probability The Newborn Is A Boy? Many Fail This Interview Question

815 views / 0 likes - added 7 years ago

This problem has been asked in job interviews. On the morning of January 1, a hospital nursery has 3 boys and some number of girls. That night, a woman gives birth to a child, and the child is placed in the nursery. On January 2, a statistician conducts a
02:45
The Day After Tomorrow Is Yesterday Riddle. Can You Solve It?

690 views / 0 likes - added 7 years ago

This puzzle is popular on Facebook and many other sites. "When the day after tomorrow is yesterday, then today will be as far from Wednesday as today was from Wednesday when the day before yesterday was tomorrow. What day is today?" Can you solve this tri
09:11 Popular
Can You Solve The Rectangle Ratio Puzzle? The Surprising Answer

837 views / 0 likes - added 7 years ago

Start with a unit square (a rectangle with both sides equal to 1, call it R1). Attach a rectangle of area 1 to its right side, then attach a rectangle of area 1 to its top. The border of this new shape is another rectangle, call it R2. We can repeat the p
04:30 Popular
Adults Are Arguing About This 3rd Grade Math Problem

882 views / 0 likes - added 7 years ago

"If Sue runs around the track twice, and John runs around the track four times more than Sue, how many times does John run around the track?" This problem was given to 3rd graders. A parent disagreed with the answer the teacher was marking. After it was p
07:49 Popular
Can You Solve The Viral 9 = 72 Puzzle? The Correct Answer Explained

1,056 views / 0 likes - added 7 years ago

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 what many people b
04:13 Popular
Can You Solve This Grade 12 Geometry Problem From Australia? The Marshmallow Chocolate Puzzle

889 views / 0 likes - added 7 years ago

A marshmallow has the shape of a cylinder with diameter 5 and height 3. A dessert is made with 24 marshmallows: there are two stacked layers of marshmallows, and each layer has 3 rows of 4 marshmallows. The gaps between the marshmallows are filled with ch
05:27 Popular
Can You Solve The Mind-Bending Self-Counting Sentence Riddle?

941 views / 0 likes - added 7 years ago

"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 is __, and of the d
06:18 Popular
Can You Solve The Diluted Wine Puzzle?

751 views / 1 likes - added 7 years ago

A servant has a method to steal wine. He removes 3 cups from a barrel of wine and replaces it with 3 cups of water. The next day he wants more wine, so he does the same thing: he removes 3 cups from the same barrel (now with diluted wine) and replaces it
06:24
Can You Solve The Missing Sock Puzzle?

610 views / 0 likes - added 7 years ago

A statistician keeps a simple wardrobe. He only purchases pairs of black socks and white socks, and he keeps all of the socks in a pile in the drawer. Recently one of the socks was lost in the laundry. The socks have a mathematical property. If you select
03:16 Popular
Can You Solve This 8th Grade Geometry Problem? 75% Got The Wrong Answer

987 views / 0 likes - added 7 years ago

What is angle A in the star-shaped figure? This problem appeared on the 1999 AMC 8 test (intended for 8th grade students in the US). Approximately 75% of test-takers did not mark the correct response. Can you figure it out? Watch the video for a solution.
03:51 Popular
Can You Solve This MIT Admissions Question? Geometry Problem, 1869

929 views / 0 likes - added 7 years ago

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 the hypotenuse divid
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Multiply Numbers By Drawing Lines

614 views / 0 likes - added 6 years ago

Gow to multiply numbers by drawing lines. Get the Multiply By Lines Book! https://www.amazon.com/gp/product/1500866148/ If you like my videos, you can support me at Patreon: http://www.patreon.com/mindyourdecisions Connect on social media. I update each s
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05:52
Can You Solve The "MEANEST" SAT Test Question Ever?

689 views / 0 likes - added 5 years ago

On the SAT exam, you have about 2 minutes to read and solve each math question. This one about averages can send you in a loop, unless you approach it systematically. In the video I also explain a shortcut to help you solve this type of problem quickly. S
05:48
What Is The Area? "You Should Be Able To Solve This"

495 views / 0 likes - added 5 years ago

Thanks to Reio in Romania for emailing me this fun problem! What is the area? This puzzle was shared with the tagline "you should be able to solve this." Solution to 5th grade Chinese challenge problem https://youtu.be/OuJQaxZvlYs My blog post for this vi
03:21 Popular
Can You Solve A Puzzle That Fooled Richard Feynman?

701 views / 0 likes - added 5 years ago

What is the radius of the circle, in simplest terms involving a, b, and c? I read that even the great mind Richard Feynman made a mistake. Watch the video to learn the common mistake and what the correct answer is. Source Feynman story http://web.media.mi
08:51 Popular
The Viral Balloon Puzzle - The REAL Answer Explained (Using Ph.D. Level Math)

760 views / 0 likes - added 5 years ago

They say only geniuses can solve this puzzle, and this time they are correct. Thanks to all patrons! Special thanks to: Shrihari Puranik Yildiz Kabaran Kyle My blog post for this video https://wp.me/p6aMk-82U Sources https://puzzling.stackexchange.com/que
05:39 Popular
Can You Solve A 5th Grade Problem From China? Find The Area Of ABCD

783 views / 0 likes - added 5 years ago

Thanks to Eric from Miami for suggesting this problem and sending a solution! The diagram shows a quadrilateral ABCD with the values for some angles and the length of AB. Can you figure out the area of ABCD? Subscribe: https://www.youtube.com/user/MindYou

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