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Como eliminar baratas a partir de sua casa em Curitiba

3 de outubro de 2017 Dicas 0

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Hey, this is Presh Talwalkar. Here's a math problem that's stumping the Internet right now. This question was asked to 5th graders in China: ''If a ship had 26 sheep and 10 goats aboard, how old is the ship's captain?'' This problem has gotten a lot of media coverage, and I even covered it in a previous video, But we all missed the real story. This problem was actually devised by French researchers nearly 40 years ago! And it does teach a valuable lesson about math class.

So in this video, I'm gonna go over the REAL story, that no media outlet has covered so far. Before I get to that, I want to quickly go over the media coverage, and what some possible answers have been proposed. So this problem really got coverage around the world. From the South China Morning Post, from RT, from the BBC, from the Washington Post and even in Newsweek.

The media coverage focused on solving the problem. The most sensible answer I saw, that was quoted in the BBC, comes from one Weiho commenter who writes: ''The total weight of 26 sheep and 10 goat is 7,700 kilograms, based on the average weight of each animal.'' Now I did a little bit of fact-checking; you would actually get 7,700 POUNDS, if you did this search in Wolfram Alpha, but, let's just forget this little nitpick and go with 7,700 kilograms, so continuing that response: ''In China, if you're driving a ship that has more than 5,000 kilograms of cargo, you need to have possessed a boat license for at least five years. The minimum age for getting a boat's license is 23, so [the captain is] at least 28.'' That's a remarkable leap in logic. But if it sounds too crazy for you, keep in mind that these kinds of deductions are very common in Sherlock Holmes stories.

Take an example from ''The Hound of the Baskervilles''. From examining a walking stick of a man he has NEVER met, Sherlock Holmes deduces the man is under 30 years old, is a family doctor and that he owns a dog. So, the official response in China, is that the question was not a mistake. It was actually meant to be open ended and encourage critical thinking, which is usually not present in Math class.

That would be the end of the story, except this problem did NOT have its source in China. The real story is the problem was originally asked by French researchers in 1979. This problem is nearly 40 years old! I learned about the problem's origin from Benjamin Dickman, who has a PhD in Mathematics Education from Columbia University. Benjamin heard about the problem, because he believes that many people in math education have heard about this problem in similar problems, and he tweeted about it.

You could check out his Twitter profile twitter.Com/benjamindickman So from the sources that he tweeted and sent, we can actually find, in 1979, French researchers asked first and second graders the following problem: "On the boat, there are 26 sheep and 10 goats. What is the age of the captain?" I couldn't believe it when I was seeing this! This problem has been asked nearly 40 YEARS AGO in ALMOST EXACTLY the same wording! So what was the point of this exercise? Well, from reading some of these sources, the researchers had expected that most students would think the question is absurd. The correct answer would have to be "there is not enough information", But what they found was shocking. More than 3/4 of students actually tried to solve the problem by manipulating the numbers.

They said something like ''Okay, the age must be 26 plus 10, which equals 36." Very few students questioned if the problem was even solvable. In fact, this was not just a fluke result. The study was replicated on a larger scale in countries including France, Germany and Switzerland, even by researchers, who thought this was not even possible. They were antagonistic to this hypothesis that students would just manipulate numbers, and they found the same thing.

Gene Wirchenko emailed me about this related problem. His blog has math and logic problems, usually simpler than mine, and it has other posts. You can visit his blog at genew.Ca So, the related question is the following: "There are 125 sheep and five dogs in a flock. How old is the shepherd?" Well once again, you would expect the ''correct'' answer, that "there is not enough information" to solve the problem.

But, researchers found shocking results again! Many students produced answers by manipulating the numbers in the question. One student reasoned along the following lines: "Well, 125 plus 5 equals 130. That's too old of an age and 125 minus 5 equals 120, that's also too old of an age. But 125 divided by 5 equals 25 sounds about right.'' So, the student concluded the shepherd is 25 years old.

So, what's the lesson in all of this? The so-called ''Chinese'' test question, that went viral was REALLY a French research question from nearly 40 years ago. For such an absurd question, the correct answer is that ''there is not enough information'' I give credit to the school in China for asking this question. We still need to improve the critical thinking skills of students in math class. We still keep thinking that every problem we get is solvable, and it should be solvable just by manipulating the numbers we get We should always think ''Does the question actually make sense?'' And '' Is there enough information to solve it?'' So that's the real story to this viral math question from China.

Thanks for watching this video. Please subscribe to my channel, I make videos on math. You can catch me on my blog, mindyourdecisions.Com/blog/ If you like this video, you can check out my books which are linked in the video description, and you can support me on Patreon. If you have a suggestion for a puzzle or a math topic, you can email me at presh [at] mindyourdecisions [dot] com And you can also catch me on social media either at MindYourDecisions or @preshtalwalkar..