Mothering Forum banner

Test Yourselves! Math Problem Solver!

1K views 23 replies 11 participants last post by  sapphire_chan 
#1 ·
Stolen from the pages of my 5th grader's math assignments....

we have come up with our answer for this, thought you all might like a brain puzzler too


Trevor enjoys helping his mother harvest cucumbers and then make pickles with them. He and his mother store the jars on 8 shelves on a triangular shaped wall. On the top shelf and the second shelf there is room for only 1 jar of pickles. The third shelf will hold 2 jars of pickles, the fourth shelf will hold 3 jars, and the fifth shelf will hold 5 jars. If this pattern continues, how many jars of pickles will be on the sixth shelf? the eighth shelf? How many jars of pickles will be on the eight shelves altogether?


These things drive me crazy!
:
 
See less See more
4
#2 ·
When I was in school I used to dislike these kinds of problems because I could never see myself arranging jars of pickles, much less in rows on shelves as they describe.

I just read about this in DaVinci code! Each two sets of numbers adds up to the third. Here are the eight shelves. You can add them up yourself, I don't feel like opening my calculator right now. :LOL

1 1 2 3 5 8 13 21
 
#4 ·
Quote:

Originally Posted by USAmma
When I was in school I used to dislike these kinds of problems because I could never see myself arranging jars of pickles, much less in rows on shelves as they describe.

I just read about this in DaVinci code! Each two sets of numbers adds up to the third. Here are the eight shelves. You can add them up yourself, I don't feel like opening my calculator right now. :LOL

1 1 2 3 5 8 13 21
That's what we came up with. I too dislike these kinds of problems. The wording is so tricky (especially for kids) I feel they try to confuse them on purpose. My DS and I went round and round as to whether the first shelf and the second shelf each hold 1 jar or they hold 1 jar collectively.

Love The DaVinci Code! I felt like I was taking a mini college course when I read that. If I had retained the info. better I would have remembered that!
 
#6 ·
Quote:

Originally Posted by Itlbokay
That's what we came up with. I too dislike these kinds of problems. The wording is so tricky (especially for kids) I feel they try to confuse them on purpose. My DS and I went round and round as to whether the first shelf and the second shelf each hold 1 jar or they hold 1 jar collectively.

Love The DaVinci Code! I felt like I was taking a mini college course when I read that.
Sounds like you and ds both think outside the box. One big reason I don't like standardized tests or nonsense problems. I never would have figured out that problem if not for the DaVinci Code. My head was swimming but it was a great read! Did you know there's an earlier book that's also good? My friend just told me and I plan to read it soon.
 
#8 ·
Quote:

Originally Posted by Dar
But this makes no sense within the context of the problem - the number in a Fibonacci series won't make a triangle. A spiral, yes, or a rectangle... not a triangle.

Dar
That's why I find this problem so confusing, it specifically asks you to follow "the pattern" to find the solution. As you said, in the context of the problem it doesn't make sense. I don't see how this solution could be applied in real life. Our solution following the pattern was the one using the Fibonacci series...yet every time I tried to make sense of that within this triangular shelf it didn't seem like it would work.

Researching on the internet the Fibonacci series is found in Pascal's triangle. http://www.goldennumber.net/pascal.htm

It still doesn't apply to this problem though.
 
#9 ·
Saw your post on the homeschooling board so I've come over to have a look.
I think your all complicating matters looking at Fibonacci and what not. LOL it's fifth grade! not twelth. Still trying to figure out how you came up with
1 1 2 3 5 8 13 21
or maybe it's just that I'm too


Surley it's 1 1 2 3 5 7 9 11 adding up to 37 jars. I simply add an extra jar on each end of each shelf. Because we're told the forth shelf holds 3 jars and the fifth holds 5 jars and so on.
I'm asuming the child is ment to picture or draw a triangular set of shelves and going up to 13 and 21 just would't fit with this.
 
#10 ·
Quote:

Originally Posted by joandsarah77
Saw your post on the homeschooling board so I've come over to have a look.
I think your all complicating matters looking at Fibonacci and what not. LOL it's fifth grade! not twelth.

Surley it's 1 1 2 3 5 7 9 11 adding up to 37 jars.



I probably owe my DS an apology because he was certain that the first and second shelf held one jar collectively.
 
#13 ·
Quote:

Originally Posted by sunnmama
The complicated answer fits the pattern, but not a triangular wall. The simple answer fits the wall, but not the pattern.

I don't like this problem, lol.

I don't either! I enjoy a challenge, just not under these circumstances
:

I am grateful that some of you have been game enough to share in our frustration!
 
#14 ·
My DS decided on using two theories/answers for his homework, the Fibonacci Series and the simpler one.

He will have no problem debating this with his teacher, and she's pretty open minded, so I'm curious to see what the outcome will be after all this thinking!!!
 
#15 ·


I have heard of fibonacci numbers but don't know what they are. I don't think that knowledge is important for this pattern. You just add the last two numbers together to get the next. That seems to me to be what the pattern is
That might be or might not be a fibonacci number thingie, but I don't see that you need to know that to get the pattern in the first place.

You guys are really confusing me, :LOL I thought it was a pretty straight forward pattern here but apparently I'm just not smart enough to be confused :LOL
 
#16 ·
Quote:

Originally Posted by Itlbokay
My DS decided on using two theories/answers for his homework, the Fibonacci Series and the simpler one.

He will have no problem debating this with his teacher, and she's pretty open minded, so I'm curious to see what the outcome will be after all this thinking!!!
Please let us know! I shared the question with another group and I they guessed the same answer. That would be funny if we were all wrong. :LOL
 
#17 ·
I find it weird that they called the shelf a triangle. I taught 5th grade last year, and this seems like a normal 5th grade standardized tests question-- except for the triangle part. by 5th grade, they are expected to be able to pick out patterns.

1 1 2 3 5 7 9 11 can't be it-- b/c the pattern doesn't work for the first 2 shelves. going from the 1st shelf to the 2nd shelf, you don't add another 2 to the row, so that can't be it. that's not a mathematical pattern.

1 1 2 3 5 8 13 etc IS a math pattern, and a 5th grader should be able to figure out that pattern without knowing anything about the da vince code.


i'm not saying all 5th graders CAN do this, just that on state tests that is the level they are suppossed to be at.

BUT, the problem is wrong. it's not a triangle. i'm trying to think of the name for the shape... it's like a long skinny triangle, but with curved sides. you can't make straight sides out of that pattern, as far as i can see.
 
#18 ·
I think the triangle component doesn't have to be a mathematical part of the problem - but merely a way to explain that the shelves are smaller at the top and get progressively larger as they go down. And if you think about it, that would make it appear like a triangle - either a right angled one like you might get under a staircase or an isosceles triangle with a wide angle at the top.

Karen
 
#19 ·
The reason I came to 1 1 2 3 5 7 9 11 was because I didn't think shelves 1-3 were part of the pattern.

Another way of looking at it, if I can explain my thoughts
Is shelf 1 has 1 jar with zero added. Shelf 2 has 1 with zero added. (so zero is added to shelves 1 and 2)
Shelf 3 has 2 which is 1 with 1 added. Shelf 4 has 3 which is 1 added to 2
(so shelves 3 and 4 have one jar added to each shelf)
Shelf 5 has 5 jars as 2 has been added, so six should also have 2 added and be 7 jars. (so shelves 5 and 6 have 2 added to each shelf)
keeping that pattern then means shelves 7 and 8 would have 3 jars added to each shelf making them hold 10 and 13 jars.
that way you have the pattern of 0 and 0 added, 1 and 1 added, 2 and 2 added and 3 and 3 added. Does that make any sense? In that case the answer would be 40 jars.
 
#20 ·
Quote:

Originally Posted by Karenwith4
And if you think about it, that would make it appear like a triangle - either a right angled one like you might get under a staircase or an isosceles triangle with a wide angle at the top.

Karen
But if you draw it out (as I did :LOL dork that I am :LOL ), it is not a triangle at all. A triangle has 3 straight sides, and this pattern creates 2 straight sides and a *curved* side.


What did the teacher say???
 
#21 ·
Homework must be a lot easier now than when I was a kid, because you can google, "He and his mother store the jars on 8 shelves on a triangular shaped wall. On the top shelf and the second shelf there is room for only 1 jar" and come up with this URL:
http://66.102.7.104/search?q=cache:4...&client=safari
(which is an html cache of a pdf file at http://community.learnnc.org/dpi/mat...G5Weeks1-4.pdf

Which says yes, this problem is meant to be a Fibonacci series, and I agree that it's a terrible question- schooly smart kids will get it (I did), struggling kids probably won't, and kids who think too much (or highly literal kids, or various other descriptions of kids who have not-bent-to-the-will-of-the-schools) will go a little too far and say it can't be the add-last-two-together answer since that doesn't make for a triangular set of shelves as stipulated by the problem.
 
#22 ·
I just couldn't figure it out. I can't get past the part that there is a triangular shaped wall. Who would have that?? I have never seen a triangular shaped wall. And if the top shelf can't hold a jar, why are they even including it in the problem?? If it can't fit a jar, it shouldn't be there.

I NEVER got word problems in school. EVER. They just never made any sense.
 
#23 ·
I was picturing an attic room, with a slanted roof. That could make a triangular wall.

This sort of thing makes me so angry. By trying to make mathematical concepts "relevant", the textbook writers make them meaningless.

Dar
 
#24 ·
Fibonnaci series would make a sort of spire shaped-triangular wall, with curvy sides, like if you squished together the edges of a bell curve. You could get a triangle shape by making the lower shelves much further apart than the upper shelves

-
-.
--
---
----

--------

-------------
etc.

It is a silly question
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top