Math

How to solve the “working together” riddle that stumps most US college students

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

Subscribe: https://www.youtube.com/user/MindYourDecisions?sub_confirmation=1

Send me suggestions by email (address in video). I consider all ideas though can’t always reply!

Why are there comments before the video is published? Get early access and support the channel on Patreon
https://www.patreon.com/mindyourdecisions

If you buy from the links below I may receive a commission for sales. This has no effect on the price for you.

Show your support! Get a mug, a t-shirt, and more at Teespring, the official site for Mind Your Decisions merchandise:
https://teespring.com/stores/mind-your-decisions

My Books
Mind Your Decisions: Five Book Compilation
https://amzn.to/2pbJ4wR
A collection of 5 books:
“The Joy of Game Theory” rated 4.1/5 stars on 44 reviews
http://amzn.to/1uQvA20
“The Irrationality Illusion: How To Make Smart Decisions And Overcome Bias” rated 3.5/5 stars on 4 reviews
http://amzn.to/1o3FaAg
“40 Paradoxes in Logic, Probability, and Game Theory” rated 4.4/5 stars on 13 reviews
http://amzn.to/1LOCI4U
“The Best Mental Math Tricks” rated 4.7/5 stars on 8 reviews
http://amzn.to/18maAdo
“Multiply Numbers By Drawing Lines” rated 4.3/5 stars on 6 reviews
http://amzn.to/XRm7M4

Mind Your Puzzles: Collection Of Volumes 1 To 3
https://amzn.to/2mMdrJr
A collection of 3 books:
“Math Puzzles Volume 1” rated 4.4/5 stars on 13 reviews
http://amzn.to/1GhUUSH
“Math Puzzles Volume 2” rated 4.5/5 stars on 6 reviews
http://amzn.to/1NKbyCs
“Math Puzzles Volume 3” rated 4.1/5 stars on 7 reviews
http://amzn.to/1NKbGlp

Connect with me
My Blog: https://mindyourdecisions.com/blog/
Twitter: https://twitter.com/preshtalwalkar
Newsletter (sent only for big news, like a new book release): http://eepurl.com/KvS0r

2017 Shorty Awards Nominee. Mind Your Decisions was nominated in the STEM category (Science, Technology, Engineering, and Math) along with eventual winner Bill Nye; finalists Adam Savage, Dr. Sandra Lee, Simone Giertz, Tim Peake, Unbox Therapy; and other nominees Elon Musk, Gizmoslip, Hope Jahren, Life Noggin, and Nerdwriter.

Products You May Like

Articles You May Like

MYSTERIOUS VIDEOS on the Internet NO ONE Can Explain…
What IS THIS???? Mind Blow #13
Duck with 3 Feet! – Smarter Every Day 25
Why you should NEVER drink alcohol
10 Craziest Crowdfunding Campaigns that Actually Succeeded!

Leave a Reply

Your email address will not be published.