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Today I want to look at a fantastically devilish RC question sent to me by one of my students yesterday (shout out, Vito!). It’s from the Official Guide Advanced book published last year.

If you don’t know about it, this book contains 8 really challenging passages that are worth going over in microscopic detail if you’re looking to build your RC skills up. The passages can be found on GMATClub (for free!). Just click the link above and copy/paste the beginning of each passage into Google to find the problem on GMATClub.

I want to look at the passage first. Don’t read it yet. Just skim your eyes over it as you scroll down…

⠀⠀⠀⠀⠀⠀⠀⠀Is there a massive black hole at the center of our
⠀⠀⠀ galaxy, the Milky Way? The evidence is inconclusive.
(5)  Just as the Sun’s mass can be determined, given
⠀⠀⠀ knowledge of other variables, by the velocity at
⠀⠀⠀ which its planets orbit, the mass at the center of the
⠀⠀⠀ Milky Way can be revealed by the velocities of stars
⠀⠀⠀ and gas orbiting the galactic center. This dynamical
(10)  evidence, based on recently confirmed assumptions
⠀⠀⠀ about the stars’ velocities, argues for an extremely
⠀⠀⠀ compact object with a mass two to three million
⠀⠀⠀ times the mass of our Sun. Although according to
⠀⠀⠀ current theory this makes the mass at the center
(15)  of the galaxy too dense to be anything but a black
⠀⠀⠀ hole, the relative lack of energy radiating from the
⠀⠀⠀ galactic center presents a serious problem. A black
⠀⠀⠀ hole’s gravity attracts surrounding matter, which
⠀⠀⠀ swirls around the black hole, emitting some energy
(20)  as it is engulfed. Scientists believe that the amount of
⠀⠀⠀ energy that escapes the black hole should be about
⠀⠀⠀ 10 percent of the matter’s rest energy (the energy
⠀⠀⠀ equivalent of its mass according to the equation
⠀⠀⠀ E=mc^2). But when the energy coming from the
(25)  galactic center is compared to widely held predictions
⠀⠀⠀ based on how much matter should be falling into a
⠀⠀⠀ theoretical central black hole, there is a discrepancy
⠀⠀⠀ by a factor of a few thousand.

Why is this passage hard?

• It’s about Science. Many students will think, “ugh, I don’t know anything about Science!” Remember, you don’t have to know anything about the topic to get all the questions correct!

• It’s all one long wall of text. It’s not very nice of them not to give us paragraphs, so we will have to subdivide the passage ourselves into manageable chunks as we read it. Look for transition words that seem like natural breaks.

Before we proceed, you might want to look at my Reddit post on Mastering RC Main Idea Questions to understand my theory on the three types of RC passages:

• Informational

• Informational + some opinion

• Persuasive

Our categorization of the passage depends on how many keywords are present that indicate the author’s emotion/opinion.

Now let’s go through the passage.

I’m going to bold and italicize any such keywords:

⠀⠀⠀⠀⠀⠀⠀⠀Is there a massive black hole at the center of our
⠀⠀⠀ galaxy, the Milky Way? The evidence is inconclusive.
(5)  Just as the Sun’s mass can be determined, given
⠀⠀⠀ knowledge of other variables, by the velocity at
⠀⠀⠀ which its planets orbit, the mass at the center of the
⠀⠀⠀ Milky Way can be revealed by the velocities of stars
⠀⠀⠀ and gas orbiting the galactic center. This dynamical
(10)  evidence, based on recently confirmed assumptions
⠀⠀⠀ about the stars’ velocities, argues for an extremely
⠀⠀⠀ compact object with a mass two to three million
⠀⠀⠀ times the mass of our Sun. Although according to
⠀⠀⠀ current theory this makes the mass at the center
(15)  of the galaxy too dense to be anything but a black
⠀⠀⠀ hole, the relative lack of energy radiating from the
⠀⠀⠀ galactic center presents a serious problem. A black
⠀⠀⠀ hole’s gravity attracts surrounding matter, which
⠀⠀⠀ swirls around the black hole, emitting some energy
(20)  as it is engulfed. Scientists believe that the amount of
⠀⠀⠀ energy that escapes the black hole should be about
⠀⠀⠀ 10 percent of the matter’s rest energy (the energy
⠀⠀⠀ equivalent of its mass according to the equation
⠀⠀⠀ E=mc^2). But when the energy coming from the
(25)  galactic center is compared to widely held predictions
⠀⠀⠀ based on how much matter should be falling into a
⠀⠀⠀ theoretical central black hole, there is a discrepancy
⠀⠀⠀ by a factor of a few thousand.

There’s not much opinion here! The author only gives us two places where he personally weighs in. I ignored the word “believe” because that is associated with the “Scientists” and not our author.

Our author says that it’s “inconclusive” as to whether there’s a black hole, and he says that there’s a “serious problem” with the theory.

Remember — you don’t have to understand all the details as you read the passage!

Things We Don’t Need to Know Right Now:

• what a black hole is

• what a galactic center is

• what “velocities” means

• what E = mc^2 means

• what EXACTLY the theory is

• etc.

There are SO MANY details in this passage!!

If we carefully pored over each and every sentence and tried to “teach” ourselves exactly what it was saying, it would take us 8-10 minutes to read this passage.

(I’m not going to do the entire Passage Map for this passage, by the way, but if you’re curious what my notes would look like for my RC passages in general, you can check out this blog post on GMAT RC strategy.)

Takeaway #1 — The harder the passage, the LESS you should be focusing/stressing out on the details.

Let’s say you have 4 questions per passage on average (and in fact, that’s the number associated with this passage). One of those questions is very likely to be Main Idea. The other three are probably going to be Detail and Inference (occasionally they throw in a Function question).

That means for this ENTIRE passage, there are only THREE questions for which you will need to go back to the passage and actually locate and understand a detail.

Why should we spend our time understanding every single sentence up front, when we’ll have to go back and re-read anyway later on, and there might only be 3 sentences we need to comprehend, anyway?

Now, since we know there’s three types of passages, we can see that with only TWO pieces of opinion, this is not going to be classified as a Persuasive passage.

And since there is some opinion, it can’t be purely Informational.

So we will classify this as an “Informational + some opinion” passage.

Now let’s take a look at the challenging question. Set a timer for 2 minutes and give it a shot!

The “serious problem” referred to in line 17 could be solved if which of the following were true?

A. Current assumptions about how much matter a black hole would engulf proved to be several thousand times too high.
B. Current assumptions about how much matter a black hole would engulf proved to be a few thousand times too low.
C. The object at the center of the Milky Way turned out to be far more dense than it is currently estimated to be.
D. The object at the center of the Milky Way turned out to be far more massive than it is currently estimated to be.
E. Matter being engulfed by a black hole radiated far more energy than is currently assumed.

Now let’s break it down:

Takeaway #2 — Always rephrase the question in simpler terms!

REPHRASE: What would solve the “problem”?

We have two tasks here:

• figure out what the heck the “serious problem” is

• figure out how to solve it

Most people will probably not try to brainstorm how to solve whatever this “serious problem” is, and I think that’s the key here. We need to answer the question posed on our own first before looking at the answer choices!

What makes this question easier is the fact that we already noticed the phrase “serious problem” as we read the passage, because it was one of the few places the author had an opinion!

Takeaway #3 — There will almost always be an Inference question asking about the Author’s Opinion.

They were nice enough to give us the line number for this question, but we didn’t need it!

“Although according to current theory this makes the mass at the center of the galaxy too dense to be anything but a black hole, the relative lack of energy radiating from the galactic center presents a serious problem*. A black hole’s gravity attracts surrounding matter…”*

Another place where a mistake could be made, strategically, is in stopping here and not continuing to scan down for anything else that describes the “problem.” There’s a bit more towards the end of the passage that elaborates:

“But when the energy coming from the galactic center is compared to widely held predictions based on how much matter should be falling into a theoretical central black hole, there is a discrepancy by a factor of a few thousand.”

To synthesize: “Serious problem” is the lack of energy in the galactic center (and there’s a discrepancy with predictions)

So, what would solve this problem?

Either the “widely held predictions” are wrong and it’s a black hole even though it falls short by a few thousand, or perhaps the measurement itself is inaccurate and there’s more energy than they thought?

PREDICTION: Measurement of Milky Way wrong or No Discrepancy.

Takeaway #4 — Always WRITE DOWN an answer in your own words before reading the answer choices!!!

Back to the answer choices:

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If RC is an area of the GMAT with which you struggle, I would suggest going through the official guide and seeing what else can be gleaned from these questions, even if you have “done” them before.

This allows us to identify what the GMAC is teaching us to look for on the actual GMAT, and can really help you raise the bar on your abilities.

So, for example, let’s take the “terrestrial snakes” passage from the OG: https://gmatclub.com/forum/in-terrestrial-environments-gravity-places-special-demands-137034.html

And we’ll specifically look at this challenging Main Idea question:

In the passage,the author is primarily concerned with doing which of the following?

(A) Explaining adaptations that enable the terrestrial snake to cope with the effects of gravitational pressure on its circulatory system

(B) Comparing the circulatory system of the sea snake with that of the terrestrial snake

(C) Explaining why the circulatory system of the terrestrial snake is different from that of the sea snake

(D) Pointing out features of the terrestrial snake’s cardiovascular system that make it superior to that of the sea snake

(E) Explaining how the sea snake is able to neutralize the effects of gravitational pressure on its circulatory system

Our breakdown might look something like:

Takeaways:

• If you’re torn between 1 topic (terrestrial) versus 2 topics (terrestrial & sea snake), you can simply count the sentences and paragraphs in which each Topic appears (for example terrestrial appears in 3 paragraphs, while sea snake appears in 1). Also there are 3 sentences that say “terrestrial snake” (5 if we include “arboreal”!), and only 2 sentences that mention the phrase “sea snake”.

• For informational passages, notice if one of the answer choice includes a keyword that is slightly more extreme than the other choices. The word “superior” should automatically knock out (D).

• Don’t be afraid to look for a thesis. Sometimes the last sentence of the first paragraph will spell it all out: “That many terrestrial snakes in similar spatial orientations do not experience this kind of circulatory failure suggests that certain adaptations enable them to regulate blood pressure more effectively in those orientations.”