#13 - Astronomers have found new evidence that the number of

[Administrator]

Complete Question Explanation

Resolve the Paradox—#/%. The correct answer choice is (A)

In this stimulus, we learn that scientists now believe that the universe has 50 billion galaxies, instead of the prior estimate of 10 billion galaxies. Though this is a significant increase in the number of galaxies, the scientists’ estimate of the total amount of mass in the universe has not significantly increased. The stimulus does not contain an argument but a set of facts that appear to conflict. Before we look at the answer choices, we want to clearly understand the conflict. In this case, we need to explain how the estimated number of galaxies in the universe quintupled without any significant increase in the amount of mass in the universe. The argument contains numerical ideas: number of galaxies and amount of mass. Even though the number of galaxies is increased, the amount of mass has not. The two numerical ideas would be expected to rise together. The correct answer choice must somehow explain how those two numbers can be accurate.

Answer choice (A): This is the correct answer choice. The stimulus states that although scientists’ estimate of the number of galaxies in the universe has quintupled, the estimated mass of the universe has not increased in a meaningful way. In order for this to be true, the mass of galaxies must be a small portion of the overall mass of the universe. This is the percentage idea needed to explain the apparent conflict in the stimulus. For example, if the mass of galaxies was 1% of the total mass of the universe, then the fact that the number of galaxies quintupled would only increase the mass of the universe slightly.

Answer choice (B): Even if the mass of a galaxy can only be roughly estimated, one would still expect the rough estimation of 40 million galaxies to significantly impact the total mass of the universe. The fact that the mass cannot be exactly determined does not meant that the scientists cannot get a rough idea of the total increase in mass. The stimulus does not say that the newly discovered galaxies are further from or closer to Earth than those previously discovered. Therefore this answer choice does not help to explain the conflict above.

Answer choice (C): Incorrect answer choices in Resolve the Paradox questions often only address one side of the paradox. This answer choice only explains why there was an increase in the number of galaxies scientists believe exist in the universe, but not why the increase did not result in a equivalent increase in the estimated amount of mass in the universe.

Answer choice (D): The scientists give information about galaxies that currently exist. The way in which galaxies are formed does not impact the number of galaxies that exist currently.

Answer choice (E): Even if the scientists cannot agree on the proper procedures for determining the mass, as long as they agree on the approximate amount of mass in the universe, the facts in the argument would not change. Further, the correct answer choice needs to make both parts of the paradox correct, and not attack the facts in the stimulus.

[jrafert]

I got this wrong while doing a practice test, and during blind review the right answer (A) seemed obvious.

This said, I was really thrown off by the question when I first took the test. I originally chose "D."

Can someone clarify why this answer is wrong in more detail?

My reasoning went like this:

If theories about how galaxies are formed are rarely affected by estimates ofd the universe's total mass, then mass and galaxy formation must not be intimately connected, IE the overall amount of mass in the universe must not be affected by the formation of galaxies.

Does my reasoning make any sense? This answer was truly confusing. I can see why "A" is right but I'm frustrated by apparent attempts to confuse the test taker. How is that a test of intelligence?

[Luke Haqq]

Hi jrafert!

Sorry to hear you're frustrated with this one, but hopefully I can help offer some clarity about (D).

That answer choice states "Theories about how galaxies are formed are rarely affected by estimates of the universe’s total mass." As I read it, this sounds backwards. The stimulus notes that there are 40 billion more galaxies in the universe than astronomers previously thought, yet their views about total mass remain unchanged. Answer (D) seems to be backwards because we're not interested in whether views about the number of galaxies are affected views about mass, but rather the converse--the paradox is that there was a change in the number of galaxies, which would initially seem to result in a change in mass too. (A) resolves that paradox because if total galaxies make up only a tiny percentage of the universe's mass, then it would make sense that estimate's about total mass remain unchanged.

And I know that the ways in which the LSAT is designed to trip up test takers can be discouraging. You're definitely right that it's not a test of intelligence. It's a test of the test taker's ability to engage in a type of reasoning peculiar to the LSAT, and to do so under time conditions. It's also worth noting that it's not necessarily a test or gauge of how well a student will do in law school. I think the short of it is that it's totally understandable to be frustrated! Hopefully in most cases you'll be able to narrow down the answer choices to one or two options. When you're down to only a couple, then it's much more manageable to be able to spot any attempts to trick the test taker--e.g., as in an answer choice that looks really good except for one word (that happens quite often on the LSAT). If you've narrowed down the answer choices to contenders, you're more likely to spot small differences.

Additionally, if you have any of the PowerScore books, I'd encourage you to look at PowerScore's discussion of Flaw in the Reasoning questions (even though this one is a resolve the paradox). Continuing to speak to your point about ways the LSAT is designed to trip up test takers, reading through some of these materials is a great way to get better at quickly spotting common techniques, flaws, and errors that the test designers repeatedly use. If you have the full-length course books, I'd specifically recommend Lesson 7-7, "The Value of Knowing Common Errors of Reasoning."

Hope that helps!

[LsatLabit]

I have purchased the LSAT preptests from LSAC and the book indicates that E is actually the correct answer. I bought the POWERSCORE preparation books and that is what I have been studying for several months now. I have now come across several questions that do not line up with the answers from LSAC. Is there a logical explanation for the confusion? I want to know because it is making me question the integrity of the material I studied provided by POWERSCORE.

[Stephanie Oswalt]

Hi LsatLabit,

Thanks for your question! I'm unfortunately not sure why LSAC would be indicating a different answer, as the correct answer for this question is indeed A."The mass of galaxies is thought..." What is the name of the LSAC publication you have?

Thanks!

[isoifer]

This might seem a bit nitpicky, but I try to keep in mind the lessons we learn through Powerscore. One thing I recall is that we should be very careful with numbers/percentages, particularly when the stimulus uses numbers and the AC uses percentages (or vice versa). I recognize here that AC A does not present a precise percentage, but how weary should we be of these sorts of distinctions? I chose C because it seemed to explain at least part of the paradox if not all of it. A seemed suspicious because of the change from numbers to a "tiny percentage."

Thank you!

[Alex Bodaken]

isoifer,

Thanks for the question! You are right to have alarm bells go off when numbers and percentages get involved, and right to note that they play a key role in this problem. That said, it does not mean that if the stimulus, for example, talks about numbers and the answer choice in question talks about percentages that this particular answer choice can't be correct - and in fact, quite often this happens when an answer choice is helping to explain seemingly confusing reasoning (as it is in this case). In answer choice (A), we are provided with a reason that the change in the number of galaxies (which looks like a major change in the stimulus) may not change the estimate of mass...if galaxies are only a tiny percentage of the overall mass of the universe, it simply doesn't matter how many there are - any change in galaxy number won't meaningfully change the overall mass of the universe.

As to answer choice (C): that the estimates of galaxies tend to grow doesn't resolve the paradox...we can assume that the astronomers are using whatever estimate they currently have to calculate mass, and so it still doesn't make sense that if the number of galaxies expands by a factor of five the overall mass wouldn't change.

Hope that helps!
Alex