Need help with question C

Dr.Peterson

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So your answer is ... 1/8 of a layer? Or what? Stating what you did in words, including what your answer is, would help us talk about it.

It appears that you found the sum of one brick and the layer of mortar below it to be 21/8 inch, and then you divided that by the 21 inch height needed. Is that really the correct operation, do you think?

One way to check is to make units explicit. You have 21/8 inch per layer, divided by 21 inches per wall; dividing inch/layer by inch/wall yields walls/layer. You want layers/wall!

You're very close to the answer.
 

Narwalalpaca12$

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could you give me an example? I don’t really understand what your saying. I got this answer checked and helped on from the math support teacher (not actual teacher) but it didn’t seem correct. I’m not saying your wrong because spheres been MANY incidents with her not helpeing the student do the problem correctly
 

HallsofIvy

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Please answer Dr. Peterson's questions. Is the answer you show 1/8? Do you really think that the wall requires "1/8 layers"? Or is it possible that you have done the calculation backwards? To find out how many layers, of thickness a are required to reach a total thickness of b, you need to divide b by a. Is that what you did?
 

lev888

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could you give me an example? I don’t really understand what your saying. I got this answer checked and helped on from the math support teacher (not actual teacher) but it didn’t seem correct. I’m not saying your wrong because spheres been MANY incidents with her not helpeing the student do the problem correctly
When in doubt feel free to come up with a simple example yourself. Solve it, then apply the same method to your problem. E.g. layer height is 3", wall height is 6". How many layers is that?
 

Narwalalpaca12$

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That’s two layers so would I do 21/8 divided by 21?
 

Dr.Peterson

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You want to divide the height of the wall by the height of one layer. The height of the wall is 21, and the height of one layer is 21/8. So isn't it clear that you want to divide 21 by 21/8?? What do you get? Does it make more sense than 1/8?
 

Narwalalpaca12$

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Well my answer is now 8 layers ounce I divided 21 and 21/8
 

Dr.Peterson

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Good. And now you can check your answer: If you have 8 layers, and each is 21/8 inch high, what is the total height?
 

Narwalalpaca12$

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21! Thanks a lot!
 
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