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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.
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. 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?
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.
... 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...
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.
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?
"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});