Trouble with Strengthen Necessary Questions

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Jimbola
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Trouble with Strengthen Necessary Questions

Postby Jimbola » Tue Sep 13, 2011 10:10 pm

This one specifically,

The folktale that claims that a rattlesnake's age can be determined from the number of sections in its rattle is false, but only because the rattles are brittle and sometimes partially or completely break off. So if they were not so brittle, one could reliably determine a rattlesnake's age simply from the number of sections in its rattle, because one new section is formed each time a rattle snake molts.

which one of the following is an assumption the argument requires in order for its conclusion to be properly drawn?

A. rattlesnakes mold exactly once a year. (what I thought was correct)
B. The rattles of rattlesnakes of different species are identical in appearance.
C. Rattlesnakes molt more frequently when young than when old.
D. The brittleness of a rattlesnake's rattle is not correlated with the length of the rattlesnake's life
E. Rattlesnakes mold as often when food is scarce as they do when food is plentiful. (how is this correct?!?!)

from December 99 LR 1, #22

Strengthen necessary questions are one of my weakest categories in LR. I think I'm missing a core concept or it's just not "clicking."

Help appreciated and thanks in advance!

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dietcoke0
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Re: Trouble with Strengthen Necessary Questions

Postby dietcoke0 » Tue Sep 13, 2011 11:45 pm

A. rattlesnakes mold exactly once a year. (Wrong IMO because we aren't looking at how many years old they are, but just a general age. I think I put this as my answer, which would be good for a human. also I believe this is a logical assumption most people shouldn't believe. Snakes molt several times a year, and I think they want you to know that? It's meant to be a wrong answer that looks good IMO.)
B. The rattles of rattlesnakes of different species are identical in appearance.(Out of scope, we don't care)
C. Rattlesnakes molt more frequently when young than when old. (wrong because
D. The brittleness of a rattlesnake's rattle is not correlated with the length of the rattlesnake's life (Wrong, close, because if they aren't healthy, they are dead, and their rattle tells us when they died)
E. Rattlesnakes mold as often when food is scarce as they do when food is plentiful. (Correct, IMO, because it tells us that molting is not a part of when they are fat and healthy, but just it happens as a timed schedule)

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Easy-E
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Re: Trouble with Strengthen Necessary Questions

Postby Easy-E » Wed Sep 14, 2011 10:04 am

Jimbola wrote:This one specifically,

The folktale that claims that a rattlesnake's age can be determined from the number of sections in its rattle is false, but only because the rattles are brittle and sometimes partially or completely break off. So if they were not so brittle, one could reliably determine a rattlesnake's age simply from the number of sections in its rattle, because one new section is formed each time a rattle snake molts.

which one of the following is an assumption the argument requires in order for its conclusion to be properly drawn?

A. rattlesnakes mold exactly once a year. (what I thought was correct)
B. The rattles of rattlesnakes of different species are identical in appearance.
C. Rattlesnakes molt more frequently when young than when old.
D. The brittleness of a rattlesnake's rattle is not correlated with the length of the rattlesnake's life
E. Rattlesnakes mold as often when food is scarce as they do when food is plentiful. (how is this correct?!?!)

from December 99 LR 1, #22

Strengthen necessary questions are one of my weakest categories in LR. I think I'm missing a core concept or it's just not "clicking."

Help appreciated and thanks in advance!


I also incorrectly chose A initially too, but this answer can actually be eliminated pretty easily. What if they molted every month? If this were the case, you could accurately determine the snakes age (12 molts = 12 months = 1 year) without the snake molting once per year.

To be honest, once you eliminate that one, I feel like E is the only legitimate choice left. The above answer explains why it is correct though.

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tehrocstar
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Re: Trouble with Strengthen Necessary Questions

Postby tehrocstar » Wed Sep 14, 2011 1:10 pm

Funny... I actually got this wring my first time too. It was definitely a time crunch thing, in retrospection, it's obvious this is wrong. Age can be measured in units other than years, just think about how we age babies.

Initially answer E didn't make sense, what I did was to simplify and rewrite what it says next to the answer choice: "snake rattles molt at consistent intervals. " using the negation technique for assumption questions it passes with flying colors.

Want_My_Life_Back
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Re: Trouble with Strengthen Necessary Questions

Postby Want_My_Life_Back » Wed Sep 14, 2011 2:08 pm

AC A sounds appealing because not only is it consistent with the argument but it would be the perfect answer to an "if true... would strengthen" type question. However it's only sufficient and not necessary.
I find the easiest way to tackle these questions is to look at each AC as its logical opposite. Which ever one causes the argument to fall apart is an assumption required by the argument.
For AC E: Rattlesnakes do not necessarily mold as often when food is scarce as they do when food is plentiful.
If this were true, it would show that the frequency with which the snakes mold can fluctuate, weakening the usefulness of the snake's rattle as a measure of time.
For AC A: Rattle snakes do not necessarily mold exactly once a year.
Even if this were true, they could still mold exactly twice a year making the snake's rattle a reliable way to determine a snake's age.

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tehrocstar
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Re: Trouble with Strengthen Necessary Questions

Postby tehrocstar » Wed Sep 14, 2011 7:22 pm

Want_My_Life_Back wrote:AC A sounds appealing because not only is it consistent with the argument but it would be the perfect answer to an "if true... would strengthen" type question. However it's only sufficient and not necessary.


That's a great point, shows the importance of really separating strengthening (hypotheticals) from necessary assumptions.

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Jimbola
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Re: Trouble with Strengthen Necessary Questions

Postby Jimbola » Thu Sep 15, 2011 10:52 am

All your input has been. Most helpful. I will try to use the negation technique with my Strengthen N's.

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Jimbola
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Re: Trouble with Strengthen Necessary Questions

Postby Jimbola » Thu Sep 15, 2011 4:16 pm

So for these types. I guess you need to really search for what the argument NEEDS to be valid, looking deeper for the more fundamental concept it needs for the thing to work. Right?

Want_My_Life_Back
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Re: Trouble with Strengthen Necessary Questions

Postby Want_My_Life_Back » Fri Sep 16, 2011 12:05 am

Yes, but for harder versions of this type of question the correct answer usually does not appear as the most desirable. They try to distract you by adding what seems to be irrelevant information such as the scarcity of food. You read this and your first reaction is to think that food has nothing to do with a rattlesnake's rattle and you dismiss it out of hand without thinking about the consequences of that statement being false.
If I told you that Joe Johnson was just elected President of the US and that he had built his political career and platform around bashing Republicans while enjoying unwavering support from his political party. Then I ask you which of these is an assumption required by my statement.
A) Joe Johnson is a Democrat who won at least 51% of the electoral college votes.
B) Joe Johnson is old enough to buy cheap, bottom shelf booze from the local rundown liquor store.
Off the bat A seems like a considerably better choice than B. But Joe could be a third party candidate or a Republican who just fancies bashing other Republicans to bolster himself. Also if there were more than two candidates you wouldn't necessarily need 51% of the votes just more than any of the other candidates. Whereas if Joe wasn't old enough to buy booze then there's no way he would meet the minimum age limit of 35 for a presidential candidate.
The moral is don't be lured in by the appeal of an answer. Look for the answer that if untrue would crumble the argument.




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