#12 - Clothes made form natural fibers such as cotton

[jlam061695]

Can someone check to make sure if I understand why E is the correct answer? I originally did not choose E, since the stimulus did not explicitly mention anything about the original state of artificial fibers. After I went back to redo the questions I missed, I attempted to diagram part of the argument that was relevant to the correct answer choice:

CO (natural fibers are tightly curled in their original state) WHT (washed at high temperatures) S (shrink)

From that, I did the contrapositive, and inferred that "not curled" is synonymous with "straight".

S (do not shrink) WHT (not washed at high temperatures) CO (not tightly curled/straight)

Is this correct?

[Jonathan Evans]

Hi, Jlam,

Let's summarize what we know here:

1) Natural fiber clothes shrink at high temperatures.

2) Artificial fiber clothes don't.

okay, so far so good.

3) The natural fibers shrink because they were originally curled but straightened to be made into cloth.

okay, cool. Now finally:

4) All fibers return to their original state when subjected to high temperatures.

Combine statement (4) with statement (2). If you know that all fibers return to their original states when subjected to high temperatures and artificial clothes don't shrink, then you have strong support for the claim that artificial fibers are straight in their original state.

Your diagramming is not quite right. It would look something like this:

1') NF OC

2') OC (shrinks in orig state)

3') AF ~(shrink in orig state)

From the contrapositive of (2') above we get ~(shrinks in orig state) ~OC, therefore we can conclude from (2') and (3') that AF ~OC. The author makes the somewhat insignificant assumption that ~OC originally straight. This is why the question is looking for what is "most strongly supported" rather than what "must be true."

As you might note, the first way of mentally cataloging your information in a more natural manner might enable you more easily to describe what's going on and reach a valid inference. Remember that symbolization is most useful as a tool to supplement or aid your understanding. You need to make a judgment call for when symbolization will help you and when it will only complicate the problem for you.

Let me explain it this way: Sometimes you feel like a curl. Sometimes you don't. Natural fibers have curls. Artificials don't.

Sorry. A little late night attempt at comedy there.

[jlam061695]

Thanks for correcting my diagram, I can understand how the inference is made now. Just one quick question/observation: I thought "most strongly supported by" is always what "must be true"? At least, that is how Powerscore teaches it?

[Claire Horan]

Hi Jlam,

"Most strongly supported by" is not the same as "must be true," and Jonathan explained why in his explanation. "Must be true" describes a situation where bare logic will get you all the way to the answer. "Most strongly supported by," in contrast, is language that allows for an answer choice that might involve some amount of assumption or inference, and you should choose the one that requires the least amount of inference or assumption. In practice, you might find that an answer to a "most strongly support by" stem actually must be true, but the testmakers are not bound to that, so you shouldn't assume it will always be the case.