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This Chinese Math Problem Has No Answer. Perhaps, It Has a Lot of Them. (washingtonpost.com)

Fifth-graders in China's Shunqing district were recently asked to answer this question: "If a ship had 26 sheep and 10 goats on board, how old is the ship's captain?" The Washington Post: The apparently unsolvable question sparked a debate over the merits of the Chinese education system and the value it places on the memorization of information over the importance of developing critical thinking skills. "Some surveys show that primary school students in our country lack a sense of critical awareness in regard to mathematics," a statement by the Shunqing Education Department posted Jan. 26 reportedly said. One student offered a pragmatic law-abiding answer: "The captain is at least 18 because he has to be an adult to drive the ship." Meanwhile on Twitter, some have gone with 42, a reference to the science fiction novel "A Hitchhiker's Guide to the Galaxy," by Douglas Adams, in which 42 is the "Answer to the Ultimate Question of Life, The Universe, and Everything." BBC: "If a school had 26 teachers, 10 of which weren't thinking, how old is the principal?" another asked. Some however, defended the school -- which has not been named -- saying the question promoted critical thinking. "The whole point of it is to make the students think. It's done that," one person commented. "This question forces children to explain their thinking and gives them space to be creative. We should have more questions like this," another said.

31 of 443 comments (clear)

  1. There is always an answer by Obfuscant · · Score: 5, Funny

    Asking questions for which there is insufficient data to determine the unique correct answer is confusing and a waste of time, because they will never see such questions in real life. Only teach them things they'll need in real life, I say. Don't fill their heads with nonsense. Every question they will need to answer in real life will have a correct answer, and they need to expect that from others.

    1. Re:There is always an answer by Obfuscant · · Score: 5, Funny

      My guess is you aren't great with critical thinking simply based off your post here.

      My guess is that you wouldn't know sarcasm if it bit you on the ass. I don't know how I could have made it any more obvious.

    2. Re:There is always an answer by edtice1559 · · Score: 4, Funny

      A tag which is apparently blocked now. Guess no more posts containing sarcasm are allowed!

    3. Re:There is always an answer by Obfuscant · · Score: 4, Insightful
      Having to use a sarcasm tag defeats the purpose of encouraging critical thinking. When the topic sentence is so clearly and patently false, maybe rethinking whether the remainder of the argument is meant to be serious or sarcastic before launching into a lecture or modding down is a good idea.

      But I see a lot of people didn't get it. Oh well.

    4. Re:There is always an answer by Obfuscant · · Score: 4, Funny

      Hoist by my own petard. I'm now stuck trying to figure out if you were using or not. You win the point.

    5. Re:There is always an answer by Hognoxious · · Score: 4, Insightful

      What have I got in my pocket?

      --
      Confucius say, "Find worm in apple - bad. Find half a worm - worse."
    6. Re:There is always an answer by alvinrod · · Score: 4, Insightful

      I'm going to assume you're being incredibly sarcastic here because life is full of problems for which there is insufficient data to determine a correct answer. There are a great many that do already have good answers, but at one point there was insufficient data to answer them.

      If you wanted to make this exercise more useful, I'd rephrase the question (to something that's not immediately obvious) and once they've figured out that they lack sufficient data, ask them what information they would need to produce an answer. Knowing that you have insufficient data to answer a question is one thing, but understanding what is missing and how to go about getting it is a highly valuable critical thinking exercise.

    7. Re:There is always an answer by Enigma2175 · · Score: 4, Informative

      Poe's law is an adage of Internet culture stating that, without a clear indicator of the author's intent, it is impossible to create a parody of extreme views so obviously exaggerated that it cannot be mistaken by some readers or viewers as a sincere expression of the parodied views.

      https://en.wikipedia.org/wiki/...

      --

      Enigma

    8. Re:There is always an answer by Scarletdown · · Score: 5, Funny

      ...at which point, he pulled out a snub nose .38 and emptied it in Goddamn's direction.

      He would have fired again, but pity stayed his hand, "A pity I had no more bullets."

      --
      This space unintentionally left blank.
    9. Re:There is always an answer by TheRaven64 · · Score: 4, Interesting

      I wouldn't complain about that exam for any snowflake reasons, I'd complain about it because it's completely ignoring the last 60 years of exam theory research if given as stated. The most obvious problems with it:

      The question difficulty needs calibrating. There are well-known tools (facility and omit rates) for doing this, but you need a very large population of exam sitters to properly calibrate an exam where every question is optional. This means that if candidate 1 answers questions 2, 3, 4, and 5 all correctly, but candidate 2 answers questions 6, 7, 8, and 9 all correctly then you almost certainly don't have enough information to be able to compare them at all, unless either you have a few tens of thousands of students sitting the exam, or you have a bank of questions that you're reusing and are doing pre-testing to calibrate them.

      The ordering with respect to cohort means that your reliability is low. A single outlier at the top end will move everyone's marks down a lot. The lack of such an outlier will move everyone's grade up a lot. If your exam is meant to actually measure anything useful and not just be a dick-waving contest, then you'll need to do some normalisation and not use the scheme that you've proposed.

      Your discrimination is likely to be all over the place. Most exams are intended to have high discrimination at specific places. For example, in admissions testing you have deselection tests that have high discrimination somewhere in the bottom half and selection tests that have high discrimination nearer the top. The first means that there's a big jump between the definite-reject and the possible-accept candidates, the second means that there's a big jump between the definite-accept and possible-accept students. For most graded exams, you want high discrimination between grade boundaries: if someone gets a B, you want to be confident that they're definitely worse than students who get an A and better than ones that get a C, but you don't care much about their ordering with respect to other students that get a B. This structure makes it almost impossible to design an exam for high discrimination.

      If you want a snowflake reason, then your exam structure is likely to penalise women if it is being administered to teenage or undergraduate-age students, because they tend to be more negatively affected by time pressure than boys of the same age (this effect reduces with age).

      TL;DR: It sounds like you like exams that don't measure anything useful, because you do well in them.

      --
      I am TheRaven on Soylent News
  2. How was this question graded? by klingens · · Score: 4, Insightful

    If the question has no answer and is supposed to foster critical or creative thinking, how did the teachers grade the answers?
    What were the actual answers? As it stands, this is bullshit "news" cause the important part of the whole incident wasn't reported. Why am I not surprised that it's "news" from Jeff Bezos' Blog?

    Did the pupils get full credit when they pointed out how the question is unanswerable? Did they get credit for the lower bound of 18? Did they get no credit for things like the 42 answer which is simply a lame old joke?

    1. Re:How was this question graded? by ShanghaiBill · · Score: 4, Insightful

      The correct answer is: Méiyou zúgòu de xìnxi. (There is not enough information).

      I used to live in Shanghai, and my (American) kids attended public schools there for several years. I was appalled at how much the math classes were based on drill, drill, drill with very little actual thinking. I am glad to see some "fuzzy" problems included.

      There are some good things about Chinese math. For instance, in America teachers say "Show your work". In China, the teachers say "Do the math in your head, and only write down the answer". The teacher will call on kids to solve a problem written on the whiteboard, and make them do it with their hands behind their back. My kids can easily add up a column of numbers in their head, so when we eat at a restaurant, I always ask them to check the bill.

    2. Re:How was this question graded? by crunchygranola · · Score: 4, Insightful

      For instance, in America teachers say "Show your work".

      This was my bane all the way through school, I like numbers and figured lots of mental tricks (natural to me) for solving things, and was familiar with lots of number patterns (like powers of two), and so much of time answers were obvious to me, but I was marked down for not "showing" the work I never did. They didn't want me to know how to find the answer, they wanted me to crank through a rote procedure. As a simple example, if you add stuff up in your head there is no work to show.

      This even showed up in calculus when one old instructor wanted me to show my use of the "three step rule" for differentiation. What "three step rule'?! It appears that at some earlier time basic transformations for differentiation, which to me was a simple one step procedure, were divided into three separate "steps" for pedagogic reasons, I guess, which were entirely unnecessary, and not found in any recent text - basically manufacturing unneeded work.

      --
      Second class citizen of the New Gilded Age
    3. Re:How was this question graded? by Anonymous Coward · · Score: 4, Insightful

      "Show your work" is shorthand for "prove you didn't cheat".
      Just dropping down an answer means that as far as they can tell you copied it off a friend, looked it up online, etc.

    4. Re:How was this question graded? by beelsebob · · Score: 4, Insightful

      The problem is that so many of those "intuitive" tricks that we build up in our heads are not actually true. We have no concrete proof that they're valid steps in the simplification of the problem. By demanding that you right down the steps you take, the teacher can point out when you take a step that doesn't actually hold up.

    5. Re:How was this question graded? by Wrath0fb0b · · Score: 5, Insightful

      I'm sorry to hear that. As an instructor, I always encouraged my students to show their work for an entirely different reason.

      As I would explain: if you do the problem correctly, you will get full credit. If you get the problem wrong, I will go through the work you've shown and try to give you as much partial credit as I can justify. If you don't show much work, I can't give you any partial credit and so you'll get zero points on the question.

      This is the only fair way to do it. Students that get 90% of a problem right should get 9/10 possible points. But to do that, you really do have to encourage them to show their work in sufficient granularity for the instructor to grade it.

    6. Re:How was this question graded? by Anonymous Coward · · Score: 4, Insightful

      The correct answer is: Méiyou zúgòu de xìnxi. (There is not enough information)

      No, the correct answer is today's date minus the captains date of birth.

    7. Re:How was this question graded? by lewiscr · · Score: 5, Insightful

      I don't know what mental shortcuts you use, but I can prove that mine are valid.

      Why would I write down 162 + 199 and add it up, when I can just mentally add 161 + 200?
      Why would I do long multiplication of 50*49, when I can do (50*50)-50 in my head?

      I once watched a class mate add zero to a number on his calculator. Can we accept that there are some mental shortcuts that are valid?

    8. Re:How was this question graded? by Pseudonym · · Score: 5, Insightful

      "Show your work" is shorthand for "prove you didn't cheat".

      That's part of it. "Show your work" also gives you partial marks if you had the correct reasoning but made a mistake somewhere along the way. It also reveals to the teacher if a large proportion of the class doesn't understand the same thing, so the teacher can concentrate on this.

      But most of all, "show your work" is what real mathematicians do for a living. If you write a paper which says "the Goldbach conjecture is true, and I know because I proved it in my head", it will not get published because you need to show your work.

      --
      sub f{($f)=@_;print"$f(q{$f});";}f(q{sub f{($f)=@_;print"$f(q{$f});";}f});
    9. Re:How was this question graded? by angel'o'sphere · · Score: 4, Insightful

      And why would you not write:
      162 + 199 = 161 + 200 = 361? Takes no time.
      And then you write: 50*49 = (50*50) -50 = 2450, takes no time either.

      If you can do stuff in your mind, you can as well write down what you did in your mind, or not?
      That is how I did it in school and no one complained.

      --
      Cost free eBook I read (by iBook/Kobo/Amazon/ObookO/Gutenberg etc.): "The Green Odyssey" by Philip Jose Farmer.
  3. the old LA one was more relevant by Joe_Dragon · · Score: 5, Funny

    1. Johnny has an AK-47 with an 80-round clip. If he misses 6 out of 10 shots and shoots 13 times at each drive-by shooting, how many drive-by shootings can he attempt before he has to reload?

    2. Jose has 2 ounces of cocaine and he sells an 8-ball to Jackson for $320 and 2 grams to Billy for $85 per gram. What is the street value of the balance of the cocaine if he doesn't cut it?

    3. Rufus is pimping for three girls. If the price is $65 for each trick, how many tricks will each girl have to turn so Rufus can pay for his $800-per-day crack habit?

    4. Jarone want to cut his 1/2 pound of heroin to make 20% more profit. How many ounces of cut will he need?

    5. Willie gets $200 for stealing a BMW, $50 for a Chevy, and $100 for a 4X4. If he has stolen 2 BMWs, 3 4X4s, how many Chevies will he have to steal to make $800?

    6. Raoul is in prison for 6 years for murder. He got $10,000 for the hit. If his common law wife is spending $100 per month, how much money will be left when he gets out of prison and how many years will he get for killing the bitch that spent his money?

    7. If the average spray can covers 22 square feet and the average letter is 3 square feet, how many letters can a tagger spray with 3 cans of paint?

    8. Hector knocked up 6 girls in his gang. There are 27 girls in the gang. What percentage of the girls in the gang has Hector knocked up?

    9. Thelma can cook dinner for her 16 children for $7.50 per night. She gets $234 a month welfare for each child. If her $325 per month rent goes up 15%, how many more children should she have to keep up with her expenses?

    10. Salvador was arrested for dealing crack and his bail was set at $25,000. If he pays a bail bondsman 12% and returns to Mexico, how much money will he lose by jumping bail?

    1. Re:the old LA one was more relevant by Joe_Dragon · · Score: 4, Funny

      11. Bernie is a lookout for the gang. Bernie has a Boa Constrictor that eats 3 small rats per week at a cost of $5 per rat. If Bernie makes $700 a week as a lookout, how many weeks can he feed the Boa on one week's income?
      12. Billy steals Joe's skateboard. As Billy skates away at 35 mph, Joe loads his .357 Magnum. If it takes Joe 20 seconds to load his magnum, how far away will Billy be when he gets whacked?

  4. At least 28 years old by Anonymous Coward · · Score: 5, Interesting

    The Washington Post article links to a BBC article containing the following:

    And of course, there's always that one person that has all the answers.

    The total weight of 26 sheep and 10 goat is 7,700kg, based on the average weight of each animal," said one Weibo commenter.

    In China, if you're driving a ship that has more than 5,000kg of cargo you need to have possessed a boat license for five years. The minimum age for getting a boat's license is 23, so he's at least 28.

  5. Fred Brooks interview question by RightwingNutjob · · Score: 4, Interesting
    if it's really as intended. But it's probably a typo that didn't get caught. They happen. Feynman has a story in one of his books about finding a math problem like

    Johnny observes three stars through his telescope. The stars' temperatures are X, Y, and Z kelvin. What is the total temperature observed?

    when he was asked to evaluate science textbooks for the school board in Pasadena.

    1. Re:Fred Brooks interview question by Zontar_Thing_From_Ve · · Score: 4, Insightful

      if it's really as intended. But it's probably a typo that didn't get caught. They happen. Feynman has a story in one of his books about finding a math problem like

      Johnny observes three stars through his telescope. The stars' temperatures are X, Y, and Z kelvin. What is the total temperature observed?

      when he was asked to evaluate science textbooks for the school board in Pasadena.

      I looked at the original article which Feynman wrote and your summary, while extremely condensed and accurate enough for here, just assumes that the reader will get the point of Feynman's dislike of the question. I bet most here will miss it. The reason that Feynman objected to the question in the textbook is that in real life there is no reason at all to add the temperatures of stars, not that the question had a horrible mistake in it. That's very different from the question in the parent article, which is to test critical thinking.

  6. This question first appeared in 1841... by DrTJ · · Score: 5, Informative

    ... and is known as the 'age of the captain' problem, introduced by Gustave Flaubert, a french writer.

    It's been used to study how children in elementary school react to word problems. It has notthing to do with maths.

    See e.g. https://www.jstor.org/stable/3...

    1. Re:This question first appeared in 1841... by geekmux · · Score: 5, Insightful

      Mod up please. This is exactly the kind of quality information that makes me read the comments before the article. The entire discussion makes no sense without knowing this. Shame on The Washington Post for publishing making this sound like some controversial idiotic thing, without providing the basic background!

      Perhaps I could help explain with a math problem. Seems fitting.

      Since hype and bullshit are proven revenue streams, how many clicks and likes does it take to dismiss journalistic integrity and relevant information?

  7. Project requirements by Moof123 · · Score: 4, Funny

    The question sounds like the quality of requirements documents I've been handed. Life is full of self-important people telling you to do the impossible with inadequate information, tools, time, and money. Sounds like the kids got an early insight into the "Joy of work."

  8. The answer is by mr.mctibbs · · Score: 4, Funny

    Whoooooosh

  9. Word problems as a test of understanding by steveha · · Score: 4, Interesting

    In one of Richard Feynman's books, he told about his experiences at a university in Brazil. He was horrified to realize that the students were ritually memorizing the course material with very little actual understanding.

    When he asked questions in a way that echoed the textbook, students were able to recite an answer straight out of the book. But when he made up a "word problem" they were totally unable to answer.

    A student was quizzed on physics, asked to compute what happens when light passes through a diamagnetic substance, and he recited the answer correctly and then calculated the correct result given the index and thickness of the substance. Immediately afterward, Feynman talked to that same student; Feynman held up a book and asked what would happen if the book was made of glass and he looked at something through the book. The student didn't realize that glass is a diamagnetic substance, and gave a very incorrect answer.

    Richard Feynman on education in Brazil

    In the domain of math questions, I saw an example: if a person has 4 boards of length 2.5 metres each, and cuts them with a saw, how many 1-metre boards can that person make? Obviously the correct answer is 8 (two per board, with 4 left-over pieces of length 0.5 metres minus the width of two saw cuts). If you were just playing with the numbers abstractly you might think that since 4 * 2.5 == 10 that you could produce ten 1-metre board segments. You can't actually glue together 4 boards to make a single board, and you can't actually make zero-width cuts.

    I can't speak for others, but I enjoy word problems more than abstract problems. (Good ones, anyway... you can take a simple problem and write an annoying and confusing word problem, and nobody likes those.)

    --
    lf(1): it's like ls(1) but sorts filenames by extension, tersely
  10. NaN by cyn1c77 · · Score: 4, Insightful

    This problem is not sufficiently bounded to solve from a mathematical perspective.

    (That's the actual answer... You don't need to be over 18 if you are piloting the boat illegally and there may not even be a captain.)