Most US College Students Cannot How Many Holes Does A Straw 5 months ago   07:14

MindYourDecisions
To complete a job, it takes: Alice and Bob 2 hours, Alice and Charlie 3 hours, and Bob and Charlie 4 hours. How long will the job take if all 3 work together? Many, many US college students set up the equations incorrectly and get the wrong answer. Can you solve it? Watch the video to understand the correct method and answer.

*Small correction: At 2:19 I incorrectly said "four fifths" and meant to say "four point five."

My blog post for this video
https://wp.me/p6aMk-5h1

Sources
Toom, Andrei. "A Russian teacher in America." Journal of Mathematical Behavior 12.2 (1993): 117-139. See the "Tom, Dick, and Harry working together problem" (page 134 in text). https://faculty.utrgv.edu/eleftherios.gkioulekas/OGS/Misc/ARUSSIAN.PDF

Jerome Dancis, Associate Professor Emeritus, University of Maryland, Algebraic word problems. www.math.umd.edu/~jnd/Algebraic_word_problems.pdf

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How Many Holes Does A Straw Most US College Students Cannot 5 months ago   04:21

This question has generated a lot of debate online. BuzzFeed's video has 450,000+ views already. But the question has a mathematical interpretation with a correct answer: in topology, how many holes does a straw have? I explain and animate the answer in the video. It's great to see topology go viral!

My blog post for this video
https://wp.me/p6aMk-5sB

BuzzFeedVideo
https://up-tube.com/upvideo/J0gLEIDiXoZ

Drinking Straws: How Many Holes? Kevin Knudson, professor of mathematics at the University of Florida
https://www.forbes.com/sites/kevinknudson/2018/01/29/drinking-straws-how-many-holes/

2016 Nobel Prize in Physics
https://www.nobelprize.org/nobel_prizes/physics/laureates/2016/

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https://www.patreon.com/mindyourdecisions

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My Books
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"The Irrationality Illusion: How To Make Smart Decisions And Overcome Bias" is a handbook that explains the many ways we are biased about decision-making and offers techniques to make smart decisions. (rated 4.6/5 stars on 3 reviews)
http://amzn.to/1o3FaAg

"Math Puzzles Volume 1" features classic brain teasers and riddles with complete solutions for problems in counting, geometry, probability, and game theory. Volume 1 is rated 4.4/5 stars on 13 reviews.
http://amzn.to/1GhUUSH

"Math Puzzles Volume 2" is a sequel book with more great problems. (rated 4.3/5 stars on 4 reviews)
http://amzn.to/1NKbyCs

"Math Puzzles Volume 3" is the third in the series. (rated 3.8/5 stars on 5 reviews)
http://amzn.to/1NKbGlp

"40 Paradoxes in Logic, Probability, and Game Theory" contains thought-provoking and counter-intuitive results. (rated 4.3/5 stars on 12 reviews)
http://amzn.to/1LOCI4U

"The Best Mental Math Tricks" teaches how you can look like a math genius by solving problems in your head (rated 4.7/5 stars on 4 reviews)
http://amzn.to/18maAdo

"Multiply Numbers By Drawing Lines" This book is a reference guide for my video that has over 1 million views on a geometric method to multiply numbers. (rated 5/5 stars on 3 reviews)
http://amzn.to/XRm7M4