LSAT PrepTest 18 Section 4 Question 10 Explanation | Logical Reasoning

I didn't write the following blog post. It was already on the blog when I took over the URL. The following blog post may contain mistakes. -Steve

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This Logical Reasoning question is from the December 1992 LSAT.

Breakdown:

Premise 1: Almost all books from the last 150 years were printed on acidic paper.

Premise 2: All acidic paper gradually destroys itself.

Premise 3: This deterioration process can be SLOWED by storing books in a cool, dry area.

Premise 4: New techniques being developed to De-Acidify books will probably only be used on historically significantly books.

This means almost all books from the last 150 years will gradually destroy themselves, unless they are de-acidified. Otherwise, this process can only be slowed, not stopped. De-acidification, however, will probably only be used on historically significant books.

Choice A is the correct answer. If a book is from this period, and is NOT historically significant, it will probably deteriorate completely, because it will probably not be de-acidified.

We can eliminate the other choices for the following reasons:

Choice B: We can't conclude that almost all the books from this period will gradually destroy themselves. Many may be historically significant, so they may be de-acidified.

Choice C: Many other kinds of books may also gradually deteriorate. Keep in mind that prior to this period, most books may have contained non-acidic paper.

Choice D: We don't know if any books had acidic paper before this period (over 150 years ago). Therefore, we can't say all books (of any group) from that time will be deacidified.

Just as importantly, being historically significant is (almost) a necessary condition, not a sufficient condition. Therefore, even if being historically significant qualifies a book for possible deacidification, it doesn't guarantee it.

Choice E: This doesn't have to be true because we know the deterioration process can be slowed down by storing the book in a cool, dry location. This means books will likely deteriorate at different rates.