#10 - Almost all of the books published in the past 150

[Administrator]

Complete Question Explanation

Must Be True-SN. The correct answer choice is (A)

The stimulus consists solely of observations, making it a “fact set.”

• 1. Almost all books published in the past 150 years used acidic paper.
  
  2. Acidic paper self-destructs.
  
  3. Storage in cool, dry environments slows the destruction.
  
  4. Treatments to de-acidify paper will probably only be applied to books with historic significance.

You are asked what must be true, so you should choose a response which either repeats the stimulus or draws a supported conclusion.

Answer choice (A): This is the correct answer choice. Probably, books of no historical significance will not receive the treatment, which means that their pages will self-destruct. The deterioration may not involve the binding directly, but it is reasonable to view books with destroyed pages as in some sense completely deteriorated.

Answer choice (B): This choice is very similar to the correct choice, but since you should not assume that almost all of the books from the past 150 years have no historical significance, you should not conclude that almost all of the books will destroy themselves. It is fairly reasonable to believe that most of the books will destroy themselves, but not that almost all of the books will destroy themselves.

Answer choice (C): The stimulus supports that untreated books made of acidic paper will deteriorate, not the Mistaken Reversal that any book that deteriorates is made of acidic paper. This response does not follow, and is incorrect.

Answer choice (D): The stimulus stated that the technique would probably be applied only to books with historic significance. That is loosely conditional, claiming that usually “technique used historical significance.” This choice renders a Mistaken Reversal, “historical significance technique used,” so this choice does not follow, and is incorrect.

Answer choice (E): Since the stimulus states that the environment in which the book is kept can affect how long it takes its pages to deteriorate, it does not make sense to conclude that all of the books published in 1900 should be in roughly the same state of deterioration.

[GLMDYP]

Hi!
For this question, I think the right answer should be (B) as well as (A). Without any de-acidification, the books published in the past 150 years will destroy themselves completely, thus (B) will be correct since it stated directly the facts.
Am I right on this one?
Thanks!

[Nikki Siclunov]

Hi GLMDYP,

We don't know if almost all the books published in the last 150 years will gradually destroy themselves. Although the techniques that de-acidify the books will be applied only to books with historical significance (De-acidify Historically significant), we don't know what proportion of all books published in the last 150 years count as "historically significant." What if almost all of them are? If so, it's entirely possible that they all undergo de-acidification, and thus only a few of the books deteriorate.

We can easily prove, however, that if a book is not historically significant, then it will not be de-acidified, and will probably deteriorate completely:

NOT historically significant NOT De-acidify Deteriorate

This is why answer choice (A) is correct, and (B) is not.

Does this help? Let me know!

Thanks.

[MikeJones]

Didn't see it at first but answer A is easily provable via the conditional logic laid out in the stimulus.

From the first two sentences you get:

Past 150 Acidic Destroys (deteriorate) itself gradually

Conclusion:

/Acidic (deacidified) Historically significant

From here you take the contrapositive and hook it up to the second sentence:

/Historically significant Acidic Destroys (deteriorates) itself gradually

Combine this with the first two sentences, Past 150 Acidic Destroys (deteriorate) itself gradually

And the answer is easily inferred from there.

[James Finch]

Hi Mike,

Exactly! Good diagramming, this is useful whenever you run into a stimulus containing conditional reasoning and can't quickly get to the correct answer.

[mrcheese]

"You don't have to accept 150/200 to be equivalent to "almost all" to know that A is not MBT. It's a fine choice for an MBA question, but it's definitely is not must be true. Any counterexample where A is not true can prove that A is not a correct choice.

Say we take "almost all" to mean 98/100 are made on acidic paper. If 97 out of those 98 are historically significant, those 97 will likely be deacidified. The 1 remaining on acidic paper will def deteriorate. Of the other 2 books are not on acidic paper may not dteriorate at all and may be historically insignificant. So, of the 3 total historically insignificant books, only 1 deteriorates and 2 don't, which is less than 50% and so A is not true in this case. Therefore A is not an MBT.

The issue arises out of "almost all" wording in the first sentence. If it were "all, or the q stem asked for a MSS, then A would be fine.

The way it's written, it's definitely a flawed question created by LSAC. This issue with this q item has to be known to experts.
Anyone find surprising that it's remained unnoticed for so long??"

It seems like this poster on another forum has a point. This question is a bad apple?

[Rachael Wilkenfeld]

Hi Mrcheese,

That's an interesting perspective. Let's think this one through using numbers to help us understand the situation.

1) Almost all books printed in the last 150 years were printed on acidic paper, which we know eventually deteriorates.

Let's say that almost all is 90/100. I'm not sure what it would be exactly, but that's in the ballpark, and fairly easy to work with.

2) Techniques to deacidify books will probably only be used on books of historical significance.

Here's the big problem---we have no idea how many books are of historical significance. Is it 90/90 that are on acidic paper? 1/90? 0/90? We can't assume any number here, so whatever answer we select has to be consistent with all those options.

Let's turn to the answer choice (A).

Answer choice (A) says that if a book was published in the last 150 years, and is historically insignificant, it will "probably" deteriorate. What does probably mean? Probably means more likely than not, so we can think of it as 51-100 percent likely.

What books is answer choice (A) talking about? It's talking about only the books that aren't historically significant. Remember, we have no idea how many books that is, but ultimately it doesn't matter. Our stimulus tells us that the techniques to deacidify will "probably" be used only on books of historical significance. This is completely consistent with answer choice (A) which says they will "probably" deteriorate. Both the stimulus and the answer choice are using consistent levels of certainty, and answer choice (A) is provably true.

I believe that the suggestion you are describing is still consistent with it being "probably" true that the book would deteriorate. "Probably" isn't anything approaching certainty. There's still plenty of possibilities that include books deteriorating, such as if 70/100 books are not historically significant and are printed on acidic paper. Or if 80/100 are. Or even 30/100. You can come up with a lot more possibilities where a book published during the last 150 years and is historically insignificant deteriorates than it doesn't. That's consistent with the conditional in answer choice (A) that is phrased in terms of "probable" occurrences.

Ultimately though, it all comes down to finding the BEST answer choice. Is there a different answer choice here that is better answer for a must be true question? They all have far bigger holes than this one.

Hope that helps!
Rachael

[megansayles7]

Hi there everyone! The thing I'm not understanding about this is that in the stimulus it states that "The process of deterioration can be slowed..." If it's only "slowed", then isn't it the case that all books will gradually destroy themselves? Even the ones stored in a cool, dry environment will still destroy themselves, it's just that the process is "slowed". This is why I still don't understand how B is incorrect.

Thanks!
Megan

[Jay Donnell]

Hi Megan!

You're totally not wrong to pick at the idea that if the deteriorating is merely 'slowed' then it suggests that at some point the books will eventually completely fade to nothing, just like the unlucky half of the Thanos snap or Melisandre (the Red Woman in Game of Thrones) without her magic necklace, if we're speaking in 2019 pop culture references...

My big issue with B is actually not in that the books will gradually destroy themselves, but in the idea that the destruction will apply to 'almost all of the books' that have been published in the past 150 years. We know that the process to delay/postpone the deterioration will only be applied to books with 'historical significance' but we have no idea exactly what that criteria may be. Perhaps every book ever published has one copy saved for posterity sake? Without knowing how broad these techniques will be applied under the vague discussion of 'historical significance' it's hard to 100% prove B with its problematic excesses in logical force with the use of 'almost all' and 'will.'

Hope that helps!

[whardy21]

I picked Answer choice B over A.. My diagram is as follows:

Sentence 1 : books published past 150 printed on acidic paper

Sentence 2: acidic paper destroys itself(gradually)

Chain Books published past 150 printer on acidic paper destroys itself gradually

Inference: book published past 150 destroys itself gradually

S3: stored in cool dry environment process of deterioration slowed

S4: technique deacidify books with Historical significance

I considered answer choice A a loser due to the word insignificant. To what extent do we except the changing of words in the stimulus and the answer choices. Please check my diagram I would like to know where I went wrong. Thanks!