PT #30, Section 2, Question 22 Forum

[lifeprincess13]

Classic question, lol...

I have looked around to see if anyone has a sufficient explanation as to why (A) is not correct, but I feel as if I can argue for (A).

If rattlesnakes do not molt exactly once a year, that means that rattlesnakes could molt 12 times a year or once every 12 years, varying with each rattlesnake. Which means that there is no consistent way to measure how many years a rattlesnake is depending on the number of sections in its rattle.

I mean, I can understand why (E) is correct, however, (A) is, in my mind, a lot stronger than (E).

...and bravo to anyone who can effectively answer this question; its one of the toughest questions I've answered. Moreover, Manhattan LSAT does not even have an explanation, and their explanations usually clear up most issues.

Thanks!

[chadbrochill]

Classic question, lol...

I have looked around to see if anyone has a sufficient explanation as to why (A) is not correct, but I feel as if I can argue for (A).

If rattlesnakes do not molt exactly once a year, that means that rattlesnakes could molt 12 times a year or once every 12 years, varying with each rattlesnake. Which means that there is no consistent way to measure how many years a rattlesnake is depending on the number of sections in its rattle.

I mean, I can understand why (E) is correct, however, (A) is, in my mind, a lot stronger than (E).

...and bravo to anyone who can effectively answer this question; its one of the toughest questions I've answered. Moreover, Manhattan LSAT does not even have an explanation, and their explanations usually clear up most issues.

Thanks!

This is a famous necessary assumption question (notice the "requires" in the question stem). If E is false, and rattlesnake molting is affected by food scarcity, then it would destroy the argument that age can be reliably determined.

There's an interview on LSATBlog of a logical reasoning writer who cited this as his favorite question b/c it really requires the ability to differentiate necessary and sufficient conditions. (Also the question stem is written pretty deceptively to mask the question type.)

Hope this helps

[lifeprincess13]

Yes, Steve; this is his favorite question. I have read what he says, but he does not explain why (A) is not right completely.

I understand why (E) is right; what I do not understand is why (A) is wrong. In my earlier post in this thread, I explained why I think (A) is absolutely necessary and I still do not get why it is not, compared with (E).

[ws81086n]

The question asks for a necessary assumption. (A) is sufficient but not necessary. (A) could just as easily say rattlesnakes molt exactly twice a year, and that would also be sufficient, i.e. the (A) we have is not necessary.

[lifeprincess13]

But even without saying that rattlesnakes molt once, twice, whatever a year, no matter what we are assuming that they molt at a certain distinguishable rate. Whether that is once a year or twice a year, it has to be consistent. (E) just maintains that other aspects of their life do not change that consistency. But (A) establishes a consistency.

[chadbrochill]

But even without saying that rattlesnakes molt once, twice, whatever a year, no matter what we are assuming that they molt at a certain distinguishable rate. Whether that is once a year or twice a year, it has to be consistent. (E) just maintains that other aspects of their life do not change that consistency. But (A) establishes a consistency.

Saying that they molt EXACTLY ONCE a year is far too strong and specific to be necessary to the argument. Take the negation, if rattlesnakes do not molt exactly once a year, is the argument false? of course not, it could be any number of different rates what makes "exactly once" so special?

Remember this is a necessary assumption question, not a sufficient, not a strengthen. Think of it as what must be true.

[ws81086n]

(A) is actually not even sufficient, on second thought, since the rattle could conceivably break off for a reason other than brittleness. And there are other holes in the argument. (E) is necessary though, since a regular molting pattern unaffected by external factors would be needed.

[lifeprincess13]

Ok...I mean, I get it. I see why (E) is better than (A). I guess when I read the stimulus and answer choice (A), I understood that there had to be some type of consistency within how to determine the age of the rattlesnake. Although I believe (E) could be stronger in establishing an actual consistency that is not broken by the amount of food being eaten, I can see why (E) is stronger than (A).

Thanks guys!