#21 - Most kinds of soil contain clay, and virtually every

[Jonathan Evans]

Hi, Liz,

That's a perfectly acceptable way to diagram this conclusion.

In the diagram above, it is implicit that we are talking about the soil when Nikki writes:
Clay Sand
"there is some clay containing soil that also contains sand"
Clay Organic Material
"there is some clay containing soil that also contains organic material"

However, it is also valid for you to write:
soil clay and sand
"there is some soil such that it contains both clay and sand"
soil clay and organic material
"there is some soil such that it contains both clay and organic material"

I hope this helps!

[Liz0501]

Hi Jonathan!

It does help, I was so caught up in the details of diagramming that I thought I was misunderstanding something about the basics when my diagram wasn't matching up with the thread lol. Thank you for the clarification!

[lemonade42]

Hello,
I'm a confused on when Nikki wrote "Thus, no conclusion can plausibly be drawn on the basis of the information presented."
Given:
Soil Clay
Soil Sand or Organic Material

Can't you go "backwards" on a Most arrow to make a Some arrow, so then you would get these conclusions?
Clay Sand
OR
Clay Organic Material

We just can't conclude what the stimulus wrote which was:
Clay Sand
AND
Clay Organic Material

[Rachael Wilkenfeld]

It's the dual conclusions that pose a large problem here, lemonade. Our statements state that most types of soil contain clay, and virtually all contain sand or organic material or both.

The following statements are consistent with the premises.

Virtually all soil contains sand, and no soil contains organic material.
Virtually all soil contains organic material, and no soil contains sand.

Because of those two possibilities, we cannot determine that there must be some type that contains both sand and clay as well as one that contains both organic material and clay.

Hope that helps!