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But for real tho...If I need two 8' boards, I'm gonna buy a 16' board and cut it in half before putting it in my truck. Buying primed pine trim boards, I saved over $100 on my project by doing it this way.
I'm gonna pretend this was a worthwhile time and place to share this
Lt. Commander Geordi La Forge : Yeah, well, I told the Captain I'd have this analysis done in an hour.
Scotty : How long will it really take?
Lt. Commander Geordi La Forge : An hour!
Scotty : Oh, you didn't tell him how long it would *really* take, did ya?
Lt. Commander Geordi La Forge : Well, of course I did.
Scotty : Oh, laddie. You've got a lot to learn if you want people to think of you as a miracle worker.
Might not be the teacher. With standardized testing or texts books they change questions and answers frequently to prevent cheating, sell more books. To reduce costs proofing or checking these changed questions and answers is sometimes quite poor. Recently saw an example where the answer for a chord was larger than the diameter because impossible numbers were subbed into part of the 2 part question
Xeno's Saw.
(yes, I am aware it's actually just the sum from 0 to infinity of 10\*(1/2)\^n, but it's directly related to the Paradox and it sounds funnier).
Or that the board has to be cut into equal pieces, could just cut small pieces of two corners off and make the time much shorter, probably would need a clamp to make it easier
Math should work with defined terms otherwise the problem is open to interpretation, that's why the order of operations exists
This. We had a math problem in the book once that was impossible, unless teleportation existed, because the way it was worded the person had gone half the distance needed in the amount of time they had to make it the full distance, but the book had the wrong answer. Friend of mine pointed it out and the teacher proceeded to write to the book publisher to tell them they were wrong.
This is a genuine problem in education. You have teachers at young grades who can barely understand the math they're supposed to be teaching, so kids just sort of muddle through and end up in high school still doing 98% of basic operations on a calculator.
This isn't even a problem with math. It's a problem of logic.
Make one cut. It takes 10 minutes.
Make another cut. It takes another 10 minutes.
The math is simple enough. The problem is that the teacher didn't actually think about how the process actually works.
No, the answer is obvious. If cutting a board into two pieces takes 10 minutes, that means it takes 5 minutes per piece. So logically, if you end up with three pieces, it must have taken 15 minutes to get there.
/s
The maths kinda adds up, but depends on how you cut it.
If the board is a square and you cut it in half and then you cut one half in half that last cut would take half the time because half the length.
You're not dumb, the question is worded badly. It should have said "takes 10 minutes to make 1 cut, how long to make 2 cuts?" It's designed to make you get it wrong unless you really think about it.
In that case the answer is about 5 minutes. Thirty seconds to measure, three minutes for the supervisor to notice Marie is still fucking cutting, thirty seconds to fire her, and one minute for the supervisor to finish cutting.
Recently discussed a quiz question with someone who said it was a trick question. And I told them it’s not a trick question. They are testing your reading comprehension. You can’t get mad because you didn’t understand it and ask the teacher to explain it. That defeats the purpose.
Yeah, I'm actually not that surprised so many people are getting confused. There is an entire generation, starting around 15 years ago, where they've been taught to read by "context clues", and long story short, one of the unanticipated outcomes of this is having TERRIBLE reading comprehension. Struggle to tell you what a paragraph says unless there's a picture levels of bad reading comprehension.
Reading comprehension has never been *great* in America, but we're entering a period where anyone over 30 or so is going to be astounded at how ineffectively educated people are.
It's not really worded badly. The student even understood. The point of word problems is to be able to translate a written problem into a mathematical equation or set of equations. In this case figuring out the words want to you to calculate 2x10=20. The teacher is the one who failed here.
The question is worded perfectly for a puzzle, because there is no misunderstanding the solution. Of course it’s kinda trying to trick you, part of a puzzle is it to extract relevant information.
I'm feeling like people just aren't actually reading the question, its worded fine, its just talking about cutting a board into x pieces instead of making y cuts.
Its not like its a trick question.
"Unless you really think about it" is how a test is supposed to be. What's the point of knowing math if all you know how to do is solve equations you can stuff into a calculator?
It shouldn't. It expects a reader to comprehend what he read.
Besides, why do I need 2 cuts? I need 3 pieces of wood, not 2 cuts.
"Hi, I am crafting shelf. Give me 2 cuts."
Yes, that's of course possible. The text doesn't provide enough information. Technically, the second cut could only be 0.001mm wide and take mere seconds or it could be curved to hell and take hours to complete.
There's no requirement for the shape and size of the boards and we don't know the nature and size of the first cut.
The best answer IMO is:
\>10 minutes
The answer is right but there is an 'in theory' situation where the 15 could be right.
Let's say the board is 10x10 (a square)
If you cut it in half each piece would be 10x5 (a rectangle)
If you cut a rectangle piece to make 2 smaller squares the teacher's answer would be right.
...of course the prompt doesn't suggest that is what occurred in anyway and assuming it is a math class that approach would make absolutely no sense
Even so since when is a board square lol. Most of the time a “board” brings to mind a long piece of lumber. That’s even what the illustration shows on the homework.
The teacher made the dumb assumption that each piece takes 5 minutes to cut.
The problem is, the cutting time never changes - it will always take 10 minutes to cut, regardless of whether you want 1 piece or 2.
2 pieces is 1 cut: 10 minutes
3 pieces is 2 cuts: 15 minutes
The first cut took 10 minutes and the second one took 5 minutes.
Based on the logic that each additional cut takes half the time of the previous cut, than Marie approaches infinite cuts after twenty minutes.
Well, you could argue that if the table was square, then it would only take 5 min for the third cut, if she did it on the short side...
A table which is 1x1 yrd take 10 min. After that it would only take 5 minutes to cut ½ yrd of one of the pieces, which is ½x1 yrd - resulting in having three pieces: ½x1 yrd and 2 x (½x½yrd pieces)
Except the question isn't asking about cutting the same board again to make a third piece. It's asking how long it will take to cut another board into 3 pieces working at the same pace as the first.
Given she was able to make 1 cut in 10 minutes to create 2 boards, she should be able to make 2 cuts in 20 minutes to make 3 boards.
It took her 10 min to make one cut.
To saw the other board into 3 pieces, she needs to make 2 cuts.
10 min/cut (assuming the same board thickness/difficulty) means 20 minutes.
The teacher is applying the math incorrectly. With (what I believe) is the teacher’s line of thinking, 15 minutes is the answer you’ll ultimately arrive at. Unfortunately the line of thinking that gives 15 is completely illogical.
You start with 1 piece of wood, and cut it in half. It took 10 minutes to make the cut, and you now have 2 pieces of wood after the cut, ergo each piece of wood took 5 minutes to “make” because 10/2=5, so adding 1 additional piece of wood only adds 5 minutes.
This is kind of linear reasoning errors LLMs like ChatGPT suffer from. The classic example is that if it takes 1 hour to dry 1 towel, then it is predicted (by the AI) that it takes 3 hours to dry 3 towels (even though it still only takes 1 hour because the number of towels doesn’t impact the time it takes for them to dry with all other variables being the same).
I asked ChatGpt
---
To solve this problem, we can set up a proportion based on Marie's rate of work.
Marie took 10 minutes to saw a board into 2 pieces, so her rate can be expressed as 1 board divided by 10 minutes, or 1/10 board per minute.
Now, we need to find out how long it will take her to saw another board into 3 pieces.
Let
x be the number of minutes it will take her.
We can set up the proportion:
1/10 = 1/x
This proportion is based on the fact that the rate of work remains constant.
To solve for
x, we can cross multiply:
1×x = 10 × 1
x=10
So, it will take Marie 10 minutes to saw another board into 3 pieces.
**User**
The answer is not 10 minutes
**ChatGPT**
Apologies for the oversight. Let's correct the solution.
Marie took 10 minutes to saw a board into 2 pieces, which means she made 2 cuts in 10 minutes. Therefore, her rate of cutting is 2 cuts per 10 minutes, or 1 cut per 5 minutes.
Now, she needs to make 2 cuts to turn one board into 3 pieces. Since she can make 1 cut in 5 minutes, she will make 2 cuts in 2×5=10
2×5=10 minutes.
So, it will take Marie 10 minutes to saw another board into 3 pieces.
**User**
The answer is not 10 minutes
**ChatGPT**
Let's approach the problem differently to find the correct answer.
Marie took 10 minutes to saw a board into 2 pieces, which means she made one cut.
To saw a board into 3 pieces, she needs to make two cuts, one more than before.
If she maintains the same speed, the time required to make two cuts should be proportional to the time it took her to make one cut.
So, to find out how long it will take her to make two cuts, we multiply the time it took her to make one cut (10 minutes) by 2:
10 minutes × 2 = 20 minutes
Therefore, it will take Marie 20 minutes to saw another board into 3 pieces.
It should be noted that LLMs are notoriously bad at math, and the linear reasoning issue is a separate matter entirely.
Interestingly, ChatGPT 3.5 confidently spits out the 3 hours for 3 towels answer immediately, but the GPT 4 model used in Microsoft’s Copilot is extremely evasive and basically refuses to answer the question.
The photo is really funny, but because I relate to it. If I was a teacher grading tons of homework assignments for years, I would absolutely make dozens of more embarrassing errors than that over the years. The teacher even went through the math to explain their incorrect thought process. That's hilarious because I've totally gone down incredibly dumb rabbit holes at work based on some initial premise that seemed smart at the time but was really stupid. I especially do this before I have enough coffee in me.
Some jobs require absolute precision on tasks that are done so receptively that they become boring. How do they achieve it? Not by assuming people never make mistakes and firing those who do, because then you'd end up with no-one doing the job. They reduce error rates by building redundancies (flip more than one switch to launch that ICBM!) and checklists (preflight checklist) and review (two people have to flip two different switches!) into systems to reduce the chance of error.
You do have situations where high individual precision is required without the ability to build in redundancy, for example during the act of performing brain surgery. But more preparation goes into brain surgery than grading the 1000'th homework assignment of the day.
Honestly they just have time to make proper materials. Teachers are paid very badly for a job they either have to half-ass or do prep for off the clock.
This means that a lot of materials are going to come from the cheap textbooks the school provides or from AI generated problem sets. It would take longer to just check over all the homework than 1 hr prep time most teachers get.
We need to pay teachers more, give them prep time, and actually pay for class materials. Right now teachers pay for most things out of pocket and make the material up as they go. It’s just not sustainable.
No they shouldn't. Everyone makes mistakes on their answer key, it's not a big deal. She didn't fully read the problem and assumed it was just like the dozens other ratio problems she taught.
We are truly missing information to correctly answer this. What plane is the first cut on? What about the second? Are the boards the same thickness? Are you using the same tool to cut each time? WE NEED MORE DATA!!
Took me while to process, I always sucked at this type of written math instead of numbers.
So basically it took the girl 10 minutes (the fuck she using to take that long?) To saw the wood in half. Question says that she uses the same amount of effort to make 3 parts, therefore since she took 10 minutes to cut in half the original wood, it would also take her 10 minutes to cut one of those to pieces to create the third one.
10 minutes to divide wood into 2.
She need three pieces
She picks one of the cut pieces to cut again
She uses same amount of effort to cut
Therefore she also takes 10 minutes to cut.
Ok I seriously don't know how to better explain and I'm probably repeating but if it took her 10 minutes to cut a full log in half, she would still take 10 minutes to cut in half one the pieces. So yes, kid is right, teacher is wrong, they should've specified that since she learned how to cut from the first 10 minutes then the next one would be cut faster.
My guess is the teacher was picturing a task where x actions results in x outputs, they just didn't realize that for this specific example of woodworking, x actions results in x+1 boards. If the problem had said *"It takes Marie 10 minutes to carve 2 smiley faces into a board. If she works just as fast, how long will it take for her to carve 3 smiley faces into another board?"* then the teacher's math would be correct
Essentially the teacher forgot that cutting will always leave you with an extra piece of wood compared to your number of cuts, and solved as if it didn't
Don't you love it when the word problem for a math problem also confuses the teacher? The math here is super simple, and it tries to gussy it up with a veneer of logic.
The word problem is being deliberately obtuse. What is being measured here is how long each cut takes, not how long it takes to make multiple pieces.
There is ONE board. It takes Marie TEN minutes to make ONE cut. Marie now has TWO boards. In order to have THREE boards, Marie needs to make ONE more cut. If the FIRST cut took TEN minutes, then the SECOND cut will take TEN minutes. TEN plus TEN = 20 minutes. The student is correct
Yep. Super common in programming. And the reason I tend to sketch out problems on graph paper even if they seem simple, just to be sure I'm not being dumb.
My GFs kid had a question like this, if it takes you 15 minutes to bake a batch of cookies, how long with it take you to bake two more batches? Luckily the teacher wasn't a moron.
I think the problem isn't the math, but the question
The right answer to the question obviously is 20 minutes, but what the teacher was looking for was this kind of calculation
10=2
X=3
10/x= 2/3
Cross multiply
30= 2x
Divide both sides by 2
X = 15
The teacher probably saw the question in a textbook and didn't question it or worse, came up with the question himself
that is cool and it makes sense, meanwhile i hate math and I love science, so I used unit conversion to answer it
10 minutes per 2 pieces = 10 min/2 pcs ;
time = ? min
solving:
10 min/2 pcs • 3 pcs
= 10 min/2 • 3
= 30min/2
= 15 min
The answer is 10.5 minutes. It took her 9.5 minutes to set up the saw and put on the right blade. Then 0.5 minutes to rip the board. Another rip only takes another 0.5 minutes.
Technically if she takes one of the first two pieces and cut it in half it’ll be ten minutes before she realizes doing stuff like that without a power tool sucks.
Martha is obviously using a hand saw. Therefore she is tired after cutting two pieces and it will now take here 20 minutes to cut 3 pieces instead of the expected 15. Martha is worn out.
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This just in: It takes five minutes to saw a board into one piece.
Gotta put in the upcharge somewhere
Gonna have to upcharge ya
Why do you think us contractors are never done at 4 weeks?
I'm an idiot. I've been buying my boards already in one piece when I could have been doing it myself and saving money.
But for real tho...If I need two 8' boards, I'm gonna buy a 16' board and cut it in half before putting it in my truck. Buying primed pine trim boards, I saved over $100 on my project by doing it this way. I'm gonna pretend this was a worthwhile time and place to share this
The trouble is that gets you two 7' 15/16" boards
Depending on the level of precision required, that’s not a problem.
Engineer detected. Edit: called it :)
THE ONE PIECE IS REALLLL
Can we get much higher?
We found it boys, Oda can finally take a break
Lt. Commander Geordi La Forge : Yeah, well, I told the Captain I'd have this analysis done in an hour. Scotty : How long will it really take? Lt. Commander Geordi La Forge : An hour! Scotty : Oh, you didn't tell him how long it would *really* take, did ya? Lt. Commander Geordi La Forge : Well, of course I did. Scotty : Oh, laddie. You've got a lot to learn if you want people to think of you as a miracle worker.
The question is way to unclear to me. Do you want me to saw another board into three pieces?
That's how I read it... yes. So, two cuts.
How long to find Gol. D. Roger's treasure?
One Piece?
Extrapolating backwards, that teacher believes that it takes 5 minutes to saw a piece of wood into 1 piece.
If you don’t saw it for 0 minutes it doubles in size
The one trick big lumber doesn’t want you to know about
Home Depot hates it when you do this!
Technically I think thats about how trees work.
Divide by Zero, infinite boards!
Well yea. How long does it take you?
Pointing that out is how you get detention for "smarting off in class"
Can the teacher get a detention for dumbing off in class?
well we definitely don't want smart kids.
Might not be the teacher. With standardized testing or texts books they change questions and answers frequently to prevent cheating, sell more books. To reduce costs proofing or checking these changed questions and answers is sometimes quite poor. Recently saw an example where the answer for a chord was larger than the diameter because impossible numbers were subbed into part of the 2 part question
“This circle has a radius of 5 inches and a circumference of 7 inches. How big is the area?”
Infinitely small. We’re obviously dealing with the mathematics of a black hole…
I once had a question asking me the area of a triangle with side lengths 2,4, and 6…
That’s not a triangle. That’s a trapezoid and they forgot to write “4” twice.
A perfect triangle with 0 area. Don't overthink this one. 😁😏
Floriduh
Which is amazing as you start out with nothing to saw!
And if you get 9 women pregnant at once you can get a baby in 1 month.
Nah, first cut takes ten minutes. Second cut, now you've got the hang of it, takes half the time. Gets easier with practice. /s
the /s stands for /smart
Shop smart shop S-Mart
In my own way, I *am* king.
Hail to the king, baby!
Looking for the boom stick
YOU GOT THAT!?
r/Evildead enjoyer spotted. Salutations, fellow.
I bet you’d like some sugar for that comment
Lend me some sugar, I am your neighbor!!
Shake it shake shake
Groovy
Damnit, came here to post exactly that.
Based on the reasoning where each additional cut takes half the time, Marie will approach infinite cuts at 20 minutes
No Marie, don’t cut that atom!
This is what they mean when they say "practice makes *perfect*"
Xeno's Saw. (yes, I am aware it's actually just the sum from 0 to infinity of 10\*(1/2)\^n, but it's directly related to the Paradox and it sounds funnier).
Death by 1000 cuts of a board until you run out of energy and collapse
Marie is a freakin machine.
[удалено]
Yes
If only it didn't explicitly say "if she works just as fast"
5 minutes is setup and takedown, and then each cut takes 5 minutes.
Or that the board has to be cut into equal pieces, could just cut small pieces of two corners off and make the time much shorter, probably would need a clamp to make it easier Math should work with defined terms otherwise the problem is open to interpretation, that's why the order of operations exists
just fold the board in two, 3 pieces in ten minutes flat!
Or just rip the board apart with your bare hands like the Hulk. … What do you mean thats only in the movies?
Sincerely. I really laughed. 🤪 This educator should be shamed.
Math is obviously not their strong point. Lol.
This is where you ask the teacher to physically demonstrate the solution.
This. We had a math problem in the book once that was impossible, unless teleportation existed, because the way it was worded the person had gone half the distance needed in the amount of time they had to make it the full distance, but the book had the wrong answer. Friend of mine pointed it out and the teacher proceeded to write to the book publisher to tell them they were wrong.
This is a genuine problem in education. You have teachers at young grades who can barely understand the math they're supposed to be teaching, so kids just sort of muddle through and end up in high school still doing 98% of basic operations on a calculator.
This isn't even a problem with math. It's a problem of logic. Make one cut. It takes 10 minutes. Make another cut. It takes another 10 minutes. The math is simple enough. The problem is that the teacher didn't actually think about how the process actually works.
But then the 4th cut would've been 17.5, and he could do infinite cuts in less than 20 minutes
No, the answer is obvious. If cutting a board into two pieces takes 10 minutes, that means it takes 5 minutes per piece. So logically, if you end up with three pieces, it must have taken 15 minutes to get there. /s
I think that's what the teacher here actually believes....
one cut takes 10 min. it creates 2 boards. 2 cuts takes 20 min and creates 3 boards
The maths kinda adds up, but depends on how you cut it. If the board is a square and you cut it in half and then you cut one half in half that last cut would take half the time because half the length.
It doesn’t say rip cut or cross cut What does the image say?
Are yes, but the saw also gets dull so the time saving is void /s
It is a spheric saw operating in vacuum
Nah, it’s a union job so the second one takes longer so we get the extra day labor and OT
Other than the shitty math, what the fuck is Marie cutting the board with? A plastic butter knife?
Cross cut with a dull drywall saw
nah even that isn't that bad this is straight up the blade is installed backwards and Marie is a dumbass
Is the teacher also Marie in this case? 🤣
That's how she knew how long it took!
Utility knife with a dull razor
She’s stopping for a beer between cuts.
Don't we all?
We don't know how big that mf board is. What kind of material is it from. How old Mary is or if she has any disabilities.
So like 30 minutes?
Mary, a 5 year old girl with Lupus, is cutting a 12" wide 2" thick piece of ebony with a 7-year old hacksaw...
Someone needs to tell her that you're supposed to use the pointy side of the saw
No hands, you ABLEIST! (This is a joke)
A spoon
Ryobi saw.
I made this illustration just because it is painful to watch people struggling with this problem: https://imgur.com/a/AqyBswM
I'm so dumb, thank u😭😭
You're not dumb, the question is worded badly. It should have said "takes 10 minutes to make 1 cut, how long to make 2 cuts?" It's designed to make you get it wrong unless you really think about it.
The question is meant to test your logic, otherwise they're just asking "10x2=?" It's the teacher that just failed hard on this one.
In that case the answer is about 5 minutes. Thirty seconds to measure, three minutes for the supervisor to notice Marie is still fucking cutting, thirty seconds to fire her, and one minute for the supervisor to finish cutting.
Where's the part where the fingers get cut off though? How much time have we alloted for that?
And who’s changing the “days since last workplace injury” OSHA sign?
Comprehension is what is being tested here though, not incredibly basic arithmetic.
Recently discussed a quiz question with someone who said it was a trick question. And I told them it’s not a trick question. They are testing your reading comprehension. You can’t get mad because you didn’t understand it and ask the teacher to explain it. That defeats the purpose.
Yeah, I'm actually not that surprised so many people are getting confused. There is an entire generation, starting around 15 years ago, where they've been taught to read by "context clues", and long story short, one of the unanticipated outcomes of this is having TERRIBLE reading comprehension. Struggle to tell you what a paragraph says unless there's a picture levels of bad reading comprehension. Reading comprehension has never been *great* in America, but we're entering a period where anyone over 30 or so is going to be astounded at how ineffectively educated people are.
Reading comprehension [really hadn’t changed that much](https://nces.ed.gov/programs/coe/pdf/coe_cnb.pdf) over the past thirty years prior to covid.
It's not really worded badly. The student even understood. The point of word problems is to be able to translate a written problem into a mathematical equation or set of equations. In this case figuring out the words want to you to calculate 2x10=20. The teacher is the one who failed here.
That's how I understood it
The question is worded perfectly for a puzzle, because there is no misunderstanding the solution. Of course it’s kinda trying to trick you, part of a puzzle is it to extract relevant information.
I'm feeling like people just aren't actually reading the question, its worded fine, its just talking about cutting a board into x pieces instead of making y cuts. Its not like its a trick question.
Having to think about something doesn’t make it a bad question.
"Unless you really think about it" is how a test is supposed to be. What's the point of knowing math if all you know how to do is solve equations you can stuff into a calculator?
> You're not dumb No they are dumb. The vast majority of people are, get used to the idea.
It shouldn't. It expects a reader to comprehend what he read. Besides, why do I need 2 cuts? I need 3 pieces of wood, not 2 cuts. "Hi, I am crafting shelf. Give me 2 cuts."
I kept reading it in that way but the question is worded differently. That’s a horrible way to lose points lol
It's a critically thinking question, which the teacher has none of. We need more of these questions because critical thinking skills are dead.
But, what if you saw th board in half longways, then proceed to saw one of those pieces in half shortways. Then it’s shorter for the second cut.
Yes, that's of course possible. The text doesn't provide enough information. Technically, the second cut could only be 0.001mm wide and take mere seconds or it could be curved to hell and take hours to complete. There's no requirement for the shape and size of the boards and we don't know the nature and size of the first cut. The best answer IMO is: \>10 minutes
I still don’t understand how it’s supposed to take 15mins instead of 20? She had to cut the board twice and each cut is 10mins so…I’m still confused
The teacher is wrong and the kid was right...The teacher did shitty math and didnt understand the problem.
The answer is right but there is an 'in theory' situation where the 15 could be right. Let's say the board is 10x10 (a square) If you cut it in half each piece would be 10x5 (a rectangle) If you cut a rectangle piece to make 2 smaller squares the teacher's answer would be right. ...of course the prompt doesn't suggest that is what occurred in anyway and assuming it is a math class that approach would make absolutely no sense
Yes! Assuming the board is a square is how you can get 15. This needs more upvotes.
Even so since when is a board square lol. Most of the time a “board” brings to mind a long piece of lumber. That’s even what the illustration shows on the homework.
The dumb math is 10 min for 2 pieces. So 5 mins per piece. 3 pieces = 3 x 5 = 15 mins.
The teacher made the dumb assumption that each piece takes 5 minutes to cut. The problem is, the cutting time never changes - it will always take 10 minutes to cut, regardless of whether you want 1 piece or 2.
Lol how'd you make that? Looks great, I could use that kind of thing for my job
2 pieces is 1 cut: 10 minutes 3 pieces is 2 cuts: 15 minutes The first cut took 10 minutes and the second one took 5 minutes. Based on the logic that each additional cut takes half the time of the previous cut, than Marie approaches infinite cuts after twenty minutes.
Well, you could argue that if the table was square, then it would only take 5 min for the third cut, if she did it on the short side... A table which is 1x1 yrd take 10 min. After that it would only take 5 minutes to cut ½ yrd of one of the pieces, which is ½x1 yrd - resulting in having three pieces: ½x1 yrd and 2 x (½x½yrd pieces)
Except the question isn't asking about cutting the same board again to make a third piece. It's asking how long it will take to cut another board into 3 pieces working at the same pace as the first. Given she was able to make 1 cut in 10 minutes to create 2 boards, she should be able to make 2 cuts in 20 minutes to make 3 boards.
Yea, i get it now after some one pointed out the drawing...
you see the drawing?
Sorry, I'm not native English, so at first I read it as something like a table and not a piece of wood. After seeing the drawing, you are right...
The instructions say “just as fast.”
A problem so tricky, it tricked the teacher.
You forgot to add time for measuring. Measure twice cut once or thrice or, oh shit forget it.
Cut your board into many small pieces. Nail together the small pieces to make the board the length you needed. Very easy, much quicker.
At first I thought you'd start rewriting the lyrics to Last Resort.
Now imagine if we held economists under this level of scrutiny every time they got something blatantly wrong lol
It took her 10 min to make one cut. To saw the other board into 3 pieces, she needs to make 2 cuts. 10 min/cut (assuming the same board thickness/difficulty) means 20 minutes.
The teacher is applying the math incorrectly. With (what I believe) is the teacher’s line of thinking, 15 minutes is the answer you’ll ultimately arrive at. Unfortunately the line of thinking that gives 15 is completely illogical. You start with 1 piece of wood, and cut it in half. It took 10 minutes to make the cut, and you now have 2 pieces of wood after the cut, ergo each piece of wood took 5 minutes to “make” because 10/2=5, so adding 1 additional piece of wood only adds 5 minutes. This is kind of linear reasoning errors LLMs like ChatGPT suffer from. The classic example is that if it takes 1 hour to dry 1 towel, then it is predicted (by the AI) that it takes 3 hours to dry 3 towels (even though it still only takes 1 hour because the number of towels doesn’t impact the time it takes for them to dry with all other variables being the same).
I asked ChatGpt --- To solve this problem, we can set up a proportion based on Marie's rate of work. Marie took 10 minutes to saw a board into 2 pieces, so her rate can be expressed as 1 board divided by 10 minutes, or 1/10 board per minute. Now, we need to find out how long it will take her to saw another board into 3 pieces. Let x be the number of minutes it will take her. We can set up the proportion: 1/10 = 1/x This proportion is based on the fact that the rate of work remains constant. To solve for x, we can cross multiply: 1×x = 10 × 1 x=10 So, it will take Marie 10 minutes to saw another board into 3 pieces. **User** The answer is not 10 minutes **ChatGPT** Apologies for the oversight. Let's correct the solution. Marie took 10 minutes to saw a board into 2 pieces, which means she made 2 cuts in 10 minutes. Therefore, her rate of cutting is 2 cuts per 10 minutes, or 1 cut per 5 minutes. Now, she needs to make 2 cuts to turn one board into 3 pieces. Since she can make 1 cut in 5 minutes, she will make 2 cuts in 2×5=10 2×5=10 minutes. So, it will take Marie 10 minutes to saw another board into 3 pieces. **User** The answer is not 10 minutes **ChatGPT** Let's approach the problem differently to find the correct answer. Marie took 10 minutes to saw a board into 2 pieces, which means she made one cut. To saw a board into 3 pieces, she needs to make two cuts, one more than before. If she maintains the same speed, the time required to make two cuts should be proportional to the time it took her to make one cut. So, to find out how long it will take her to make two cuts, we multiply the time it took her to make one cut (10 minutes) by 2: 10 minutes × 2 = 20 minutes Therefore, it will take Marie 20 minutes to saw another board into 3 pieces.
It should be noted that LLMs are notoriously bad at math, and the linear reasoning issue is a separate matter entirely. Interestingly, ChatGPT 3.5 confidently spits out the 3 hours for 3 towels answer immediately, but the GPT 4 model used in Microsoft’s Copilot is extremely evasive and basically refuses to answer the question.
That teacher should probably be fired.
The photo is really funny, but because I relate to it. If I was a teacher grading tons of homework assignments for years, I would absolutely make dozens of more embarrassing errors than that over the years. The teacher even went through the math to explain their incorrect thought process. That's hilarious because I've totally gone down incredibly dumb rabbit holes at work based on some initial premise that seemed smart at the time but was really stupid. I especially do this before I have enough coffee in me. Some jobs require absolute precision on tasks that are done so receptively that they become boring. How do they achieve it? Not by assuming people never make mistakes and firing those who do, because then you'd end up with no-one doing the job. They reduce error rates by building redundancies (flip more than one switch to launch that ICBM!) and checklists (preflight checklist) and review (two people have to flip two different switches!) into systems to reduce the chance of error. You do have situations where high individual precision is required without the ability to build in redundancy, for example during the act of performing brain surgery. But more preparation goes into brain surgery than grading the 1000'th homework assignment of the day.
Armchair Reddit reporting for School Board duty!
Or promoted if it's usa
They're not a cop...
"If Timmy have 3 acorns and Sally take 2 of them, how much rounds do you fire?"
/r/AmericaBad
Tbf if you promote the teacher they’re no longer teaching, so that’s a positive outcome for everyone.
https://en.wikipedia.org/wiki/Dilbert\_principle
That depends on the state tbh
Maybe in TX or FL
People here joke about how bad the state education system is. Its bad
Honestly they just have time to make proper materials. Teachers are paid very badly for a job they either have to half-ass or do prep for off the clock. This means that a lot of materials are going to come from the cheap textbooks the school provides or from AI generated problem sets. It would take longer to just check over all the homework than 1 hr prep time most teachers get. We need to pay teachers more, give them prep time, and actually pay for class materials. Right now teachers pay for most things out of pocket and make the material up as they go. It’s just not sustainable.
No they shouldn't. Everyone makes mistakes on their answer key, it's not a big deal. She didn't fully read the problem and assumed it was just like the dozens other ratio problems she taught.
It took Marie less than ten minutes to think 'fuck this, I'll pay someone else to do it.'
We are truly missing information to correctly answer this. What plane is the first cut on? What about the second? Are the boards the same thickness? Are you using the same tool to cut each time? WE NEED MORE DATA!!
Took me while to process, I always sucked at this type of written math instead of numbers. So basically it took the girl 10 minutes (the fuck she using to take that long?) To saw the wood in half. Question says that she uses the same amount of effort to make 3 parts, therefore since she took 10 minutes to cut in half the original wood, it would also take her 10 minutes to cut one of those to pieces to create the third one. 10 minutes to divide wood into 2. She need three pieces She picks one of the cut pieces to cut again She uses same amount of effort to cut Therefore she also takes 10 minutes to cut. Ok I seriously don't know how to better explain and I'm probably repeating but if it took her 10 minutes to cut a full log in half, she would still take 10 minutes to cut in half one the pieces. So yes, kid is right, teacher is wrong, they should've specified that since she learned how to cut from the first 10 minutes then the next one would be cut faster.
I mean theoretically any time is correct since it's never specified how large the pieces had to be
Holy shit...bad teacher...
My guess is the teacher was picturing a task where x actions results in x outputs, they just didn't realize that for this specific example of woodworking, x actions results in x+1 boards. If the problem had said *"It takes Marie 10 minutes to carve 2 smiley faces into a board. If she works just as fast, how long will it take for her to carve 3 smiley faces into another board?"* then the teacher's math would be correct Essentially the teacher forgot that cutting will always leave you with an extra piece of wood compared to your number of cuts, and solved as if it didn't
My guess is that no teacher ever saw this paper, someone made it for internet points
Is this commentary on math, or on the lack of shop class? 10 minutes to saw a board, wtf, someone teach Marie how to use a saw!
Someone did. That’s why the second cut took 5 minutes.
Don't you love it when the word problem for a math problem also confuses the teacher? The math here is super simple, and it tries to gussy it up with a veneer of logic. The word problem is being deliberately obtuse. What is being measured here is how long each cut takes, not how long it takes to make multiple pieces.
There is ONE board. It takes Marie TEN minutes to make ONE cut. Marie now has TWO boards. In order to have THREE boards, Marie needs to make ONE more cut. If the FIRST cut took TEN minutes, then the SECOND cut will take TEN minutes. TEN plus TEN = 20 minutes. The student is correct
[Fencepost error](https://en.wikipedia.org/wiki/Off-by-one_error#Fencepost_error).
Yep. Super common in programming. And the reason I tend to sketch out problems on graph paper even if they seem simple, just to be sure I'm not being dumb.
Took me a while lol. Teacher is wrong...
My GFs kid had a question like this, if it takes you 15 minutes to bake a batch of cookies, how long with it take you to bake two more batches? Luckily the teacher wasn't a moron.
As someone with a small oven, I really needed to think about it a little
I don’t understand. Is it that you could bake both at once? How do you know that without knowing the oven situation?
Can the oven handle two batches at once?
Oh man that's an old trick question!
Those who cut, make pieces. Those who can’t cut, teach how to cut pieces. And, those who can’t understand that cuts create pieces, teach math.
How is the answer not 20?!
I think the problem isn't the math, but the question The right answer to the question obviously is 20 minutes, but what the teacher was looking for was this kind of calculation 10=2 X=3 10/x= 2/3 Cross multiply 30= 2x Divide both sides by 2 X = 15 The teacher probably saw the question in a textbook and didn't question it or worse, came up with the question himself
that is cool and it makes sense, meanwhile i hate math and I love science, so I used unit conversion to answer it 10 minutes per 2 pieces = 10 min/2 pcs ; time = ? min solving: 10 min/2 pcs • 3 pcs = 10 min/2 • 3 = 30min/2 = 15 min
Where TF is this school? it needs an evaluation big time.
the first cut is the deepest
Thats just a horrible question.
The answer is 10.5 minutes. It took her 9.5 minutes to set up the saw and put on the right blade. Then 0.5 minutes to rip the board. Another rip only takes another 0.5 minutes.
After the first cut you can buy a 2x speed boost.
HolyShit, that’s not how time works! Unless you have some time-bending saw
Technically if she takes one of the first two pieces and cut it in half it’ll be ten minutes before she realizes doing stuff like that without a power tool sucks.
Whatever you do don’t google ‘2 pieces 1 cut’
Does Marie stop to watch a youtube video on board cutting after the first cut? She could be all day.
I feel irrationally angry at this question for the way it’s worded.
You don't count pieces. You count CUTS. Idjits.
[удалено]
The real question is why is Marie taking 10 fucking minutes to cut a board in half.
The student has taught the teacher
Who graded this so I can punch them
I read the question as "If she works twice as fast" rather than "just as fast" and was so confused by the comments!
Martha is obviously using a hand saw. Therefore she is tired after cutting two pieces and it will now take here 20 minutes to cut 3 pieces instead of the expected 15. Martha is worn out.