We’re going to kill two birds with one stone in this week’s article.
Inference questions pop up on both Critical Reasoning (CR) and Reading Comprehension (RC), so you definitely want to master these. Good news: the kind of thinking the test-writers want is the same for both question types. Learn how to do Inference questions on one type and you’ll know what you need to do for the other!
That’s actually only one bird. Here’s the second: both CR and RC can give you science-based text, and that science-y text can get pretty confusing. How can you avoid getting sucked into the technical detail, yet still be able to answer the question asked? Read on.
Try this GMATPrep® CR problem out (it’s from the free practice tests) and then we’ll talk about it. Give yourself about 2 minutes (though it’s okay to stretch to 2.5 minutes on a CR as long as you are making progress.)
“Increases in the level of high-density lipoprotein (HDL) in the human bloodstream lower bloodstream cholesterol levels by increasing the body’s capacity to rid itself of excess cholesterol. Levels of HDL in the bloodstream of some individuals are significantly increased by a program of regular exercise and weight reduction.
“Which of the following can be correctly inferred from the statements above?
“(A) Individuals who are underweight do not run any risk of developing high levels of cholesterol in the bloodstream.
“(B) Individuals who do not exercise regularly have a high risk of developing high levels of cholesterol in the bloodstream late in life.
“(C) Exercise and weight reduction are the most effective methods of lowering bloodstream cholesterol levels in humans.
“(D) A program of regular exercise and weight reduction lowers cholesterol levels in the bloodstream of some individuals.
“(E) Only regular exercise is necessary to decrease cholesterol levels in the bloodstream of individuals of average weight.”
Got an answer? (If not, pick one anyway. Pretend it’s the real test and just make a guess.) Before we dive into the solution, let’s talk a little bit about what Inference questions are asking us to do.
Inference questions are sometimes also called Draw a Conclusion questions. I don’t like that title, though, because it can be misleading. Think about a typical CR argument: they usually include a conclusion that is…well…not a solid conclusion. There are holes in the argument, and then they ask you to Strengthen it or Weaken it or something like that.
The newest GMAT Strategy Guides have hit the shelves! We’ve been working all year on updating our materials to give you the best and most up-to-date study materials possible.
What’s so great about the new books?
So many things, I don’t know where to start! Okay, let’s talk about quant first.
Every quant book contains between 1 and 3 entirely new chapters. These chapters are devoted to strategies that will help you solve quant problems more efficiently and more effectively. These strategies are a crucial reason why all of our teachers score in the 99th percentile on the GMAT (I certainly wouldn’t consider taking the test without using them). We’ve always taught them in class and now we’re putting them in our books for the first time.
These strategies include:
Choosing Smart Numbers: you can turn certain algebra problems into arithmetic problems by substituting in your own numbers for the variables. We’re all better at arithmetic than we are at algebra, so you’ll definitely make your life easier (and be able to answer harder questions) by choosing smart numbers.
Testing Cases: On many data sufficiency problems (and even some problem solving problems), you’ll want to test cases in order to determine whether a statement is sufficient (or to eliminate wrong answers on PS). These problems are “theory” problems: the question may ask “Is n odd?” and then provide information that doesn’t allow you to determine a specific value for n, just whether specific characteristics are true of n.
Working Backwards: Sometimes, the problem is pretty annoying to set up and solve but the answers are all “nice” numbers: relatively small integers. In this case, you may be able to work backwards from the answers: pick one and try it in the problem to see whether it’s correct. The beauty of this technique: if you get good at it, on many problems you won’t have to try more than two answers in order to get to the correct one. I tested three answers on the solution in the article linked here, but I only really needed to test the first two; see if you can figure out why.
Estimation: Sometimes, the problem would be really irritating to solve exactly, but the answers are all decently spread apart. When this is the case, you can just estimate to solve! There are also a bunch of strategies for jumping between fractions, decimals, and percents to solve more quickly.
Combos: The GMAT likes to ask us to solve for a combination of variables, such as x + y. Sure, it’s possible that you may have to find x and y individually and then add them up, but it’s actually more likely that you’ll want to solve directly for that combo (x + y), especially on Data Sufficiency. Learn how to do this and also how to avoid DS traps in which the statement is not sufficient to solve for the individual variables but is sufficient to solve for the Combo.
Draw It Out: You can often solve the extra-annoying story problems, such as rates & work, via a “back of the envelope” approach: you sketch out a picture of the scenario and just “step” through it. For instance, you’d draw a timeline and map out exactly where those two trains are after 1 hour, 2 hours, 3 hours. It’s a little bit shocking how often this kind of strategy will get you all the way down to a single answer.
What is the best way to use the books?
I’ll leave you with a few tips about studying for quant. First, here’s the order that we use in our own classes:
- Fractions, Decimals, & Percents
- Word Problems
- Number Properties
I actually think Number Properties is a more important topic than Geometry, but geo requires you to memorize a bunch of formulas; that takes some time, so we do it in class first. If you feel okay with that type of memorization, then do the Number Properties book first. (By the way, the Geometry Guide now contains a 1-page sheet with all of the important rules and formulas to memorize! Tear it right out and keep it handy for studying or use it to make flash cards for yourself.)
Next, I’d recommend starting with a few problems from the problem set at the end of the chapter—that’s right, before you even read the chapter! This creates curiosity, which really wakes your brain up and primes it to learn. Don’t do a bunch and don’t do the hardest ones (unless you think you’re really good at that topic). Just do about 2 or 3 problems and then dive into the chapter. (This will also help you to know how much time you’re likely going to want to spend on the chapter; if the problems are really a struggle, you may even want to review the equivalent chapter in our Foundations of Math Guide, if you have that book too.)
When you get to the end of the main chapters of that book, do the OG Mixed Questions Quiz that we’ve devised for you. (Certain longer books also have mid-way quizzes.) You can find these quizzes on our web site, where our Official Guide Problem Set study lists live. You’ll receive access to these problem sets and quizzes, along with other bonus materials, when you register your books on our site.
We moved the OG problem sets online because GMAC is going to start publishing new versions of their Official Guide books every year (in July, we’ve heard), so by moving the problem sets online, we’ve ensured that you’ll always be able to go and get the sets for the specific OG editions that you own.
I also have a ton of updates to share on the Verbal side as well, which are detailed in Part II. Also, a plea: if you get the new books, tell me what you think down in the comments. (Compliments or criticisms—I do want both.)
Studying for the GMAT? Take our free GMAT practice exam or sign up for a free GMAT trial class running all the time near you, or online. And, be sure to find us on Facebook and Google+,LinkedIn, and follow us on Twitter!
We’ve done a lot of RC over the years, but a passage contains so much text that I rarely do a full passage with all of its questions.
We’re going to remedy that, starting today! First, we’ll talk about the passage below (from the free problem set that comes with GMATPrep®). Then, we’ll tackle the series of questions that comes with it.
Give yourself approximately 2.5 to 3 minutes to read the below and make yourself a light Passage Map.
* ” The modern multinational corporation is described as having originated when the owner-managers of nineteenth-century British firms carrying on international trade were replaced by teams of salaried managers organized into hierarchies. Increases in the volume of transactions in such firms are commonly believed to have necessitated this structural change. Nineteenth-century inventions like the steamship and the telegraph, by facilitating coordination of managerial activities, are described as key factors. Sixteenth- and seventeenth-century chartered trading companies, despite the international scope of their activities, are usually considered irrelevant to this discussion: the volume of their transactions is assumed to have been too low and the communications and transport of their day too primitive to make comparisons with modern multinationals interesting.
“In reality, however, early trading companies successfully purchased and outfitted ships, built and operated offices and warehouses, manufactured trade goods for use abroad, maintained trading posts and production facilities overseas, procured goods for import, and sold those goods both at home and in other countries. The large volume of transactions associated with these activities seems to have necessitated hierarchical management structures well before the advent of modern communications and transportation. For example, in the Hudson’s Bay Company, each far-flung trading outpost was managed by a salaried agent, who carried out the trade with the Native Americans, managed day-to-day operations, and oversaw the post’s workers and servants. One chief agent, answerable to the Court of Directors in London through the correspondence committee, was appointed with control over all of the agents on the bay.
“The early trading companies did differ strikingly from modern multinationals in many respects. They depended heavily on the national governments of their home countries and thus characteristically acted abroad to promote national interests. Their top managers were typically owners with a substantial minority share, whereas senior managers’ holdings in modern multinationals are usually insignificant. They operated in a preindustrial world, grafting a system of capitalist international trade onto a premodern system of artisan and peasant production. Despite these differences, however, early trading companies organized effectively in remarkably modern ways and merit further study as analogues of more modern structures.”
What did you get out of the passage? My thoughts (by paragraph) are on the left and my notes are on the right:
They manage to pick such interesting topics for RC, don’t they? It’s always the kind of thing you’d choose to read at home in your free time!
Wait. No, that’s not quite right. But the topics are relevant to business school… well, occasionally. Hmm.
So, let me get this straight. They’re going to give me somewhat obscure, very dense topics with very complicated ideas and sentence structures. I’m going to have about 3 minutes to read such a passage, and then I have to start answering questions about the material. That’s completely artificial; it would never happen in the real world!
Actually, yes it will. You’re going to do case studies in business school. You often won’t be given enough time to read through every last detail carefully; instead, you’ll have to figure out what’s important and concentrate on those pieces, while putting together a framework for the main ideas and the big changes in direction or opinion.
At work, you’re often going to have to make decisions based upon incomplete information. At times, you’ll have a ton of information—and not enough time to review it all before you have to take action. These situations are far from rare in the real world.
So when you find yourself a bit unmotivated because you know you’ve got to study boring RC today, remind yourself that RC will actually help you develop much-needed skills for business school and beyond!
The Master List
I’ve put together what I’m calling the Master Resource List for this question type. A couple of disclaimers. First, this list includes only free resources, no paid ones. There are a lot of good resources out there that cost some money—they’re just not on this list!
Second, this list is limited to my own articles. I’m not trying to claim that only my articles are good enough to make such a list—far from it. I’m most familiar with my own articles, so that’s what I’m using. And, okay, I will admit that I think the Manhattan GMAT RC process is the best one out there. But I’m biased. : )
How To Read
Before you dive into individual question types, it’s critical to know some overall processes for Reading Comp, starting with how to read! You already know how to read in general, of course. I’m talking about How To Read RC.
Imagine two friends, Gina and Tina, who are going to a speed-dating event. Gina really, really wants a boyfriend. Tina is just going because Gina dragged her there, and she’s only willing to date someone who is perfect for her.
At the event, Gina finds herself liking every guy that she meets: Guy #1 is smart and successful, so it makes sense that he’s proud of his accomplishments. Guy #2 is really funny and clever. The waiter just didn’t understand his jokes. Tina, on the other hand, has a very different impression of these guys: Guy 1 has been bragging about himself the whole time, and seems arrogant. Guy 2 thinks he’s funny, but he’s actually being cruel and making fun of people.
At the end of the event, Gina can’t decide which of the guys she likes best, because she’s found reasons to like all of them and she’s overlooked any reasons not to like them. Tina, however, was looking for reasons not to date these guys, so she noticed the dealbreaker flaws. She manages to whittle the list down to one guy whose personality matched hers.
Of course, dating is subjective, and what might be a dealbreaker for one person might be fine for someone else. On the GMAT, though, there are definitive right and wrong answers, and we have to learn how to spot the wrong ones.
Look for Dealbreakers
When it comes to Reading Comprehension on the GMAT, you want to act like Tina, not Gina! You will often be presented with questions whose answer choices all seem to have appealing qualities. If you’re looking for what makes an answer right, you may overlook certain critical flaws, and talk yourself into a wrong answer. If you’re looking for what makes an answer wrong, though, you’re a lot more likely to notice those deal-breaking flaws!
In the past, we’ve done some one-off review of parts of RC passages, but this time I’ve got a full one for you. In this article, we’ll look at how to get through this thing (and what to avoid). Next week, we’ll do a question or two.
I chose this passage from the free set of questions that comes with GMATPrep (that is, it doesn’t actually show up in the practice CAT itself). It’s a longer passage, so give yourself approximately three minutes total to get through.
A meteor stream is composed of dust particles that have been ejected from a parent comet at a variety of velocities. These particles follow the same orbit as the parent comet, but due to their differing velocities they slowly gain or fall behind the disintegrating comet until a shroud of dust surrounds the entire cometary orbit. Astronomers have hypothesized that a meteor stream should broaden with time as the dust particles’ individual orbits are perturbed by planetary gravitational fields. A recent computer-modeling experiment tested this hypothesis by tracking the influence of planetary gravitation over a projected 5,000-year period on the positions of a group of hypothetical dust particles. In the model, the particles were randomly distributed throughout a computer simulation of the orbit of an actual meteor stream, the Geminid. The reseNavigator found, as expected, that the computer-model stream broadened with time. Conventional theories, however, predicted that the distribution of particles would be increasingly dense toward the center of a meteor stream. Surprisingly, the computer-model meteor stream gradually came to resemble a thick-walled, hollow pipe.
Whenever the Earth passes through a meteor stream, a meteor shower occurs. Moving at a little over 1,500,000 miles per day around its orbit, the Earth would take, on average, just over a day to cross the hollow, computer-model Geminid stream if the stream were 5,000 years old. Two brief periods of peak meteor activity during the shower would be observed, one as the Earth entered the thick-walled pipe and one as it exited. There is no reason why the Earth should always pass through the stream’s exact center, so the time interval between the two bursts of activity would vary from one year to the next.
Has the predicted twin-peaked activity been observed for the actual yearly Geminid meteor shower? The Geminid data between 1970 and 1979 show just such a bifurcation, a secondary burst of meteor activity being clearly visible at an average of 19 hours (1,200,000 miles) after the first burst. The time intervals between the bursts suggest the actual Geminid stream is about 3,000 years old.
Here’s how to read
When you’re reading an RC passage, think about:
(1) What words or parts of the sentence are so complex that I’m going to ignore them for now?
(2) When can I stop reading and start skimming?
(3) When do I have to start paying close attention again?
Below, I go through each paragraph, noting various things. Normal text means: I did read this but didn’t pay extra attention to it. Boldface text really stood out for me: my brain perked up and paid attention.
It’s kind of ironic that, in order to do a great job on RC, we actually have to learn what NOT to read. You may already have read an earlier article of mine on this same topic; I want to revisit the issue not only because so many people struggle with it but also because we used an MGMAT example last time. This time, we’re going to use an example from OG13 “ that is, the real thing.
You need to do a little prep before you can get the most out of this article. First, read the introduction entitled How To Read A Reading Comp Passage. (Hint: take some notes! You’re going to be trying this out on a real passage in a few minutes!)
Next, you are going to need OG13 in order to do this exercise “ I can’t reproduce the entire passage here for copyright reasons. We’re looking for the second-to-last passage; it’s on page 414 and begins All the cells in a particular plant
Here’s what to do: set a timer for 3 minutes, read, and take whatever notes you like. If the timer buzzers before you’re done, take note. You can then go ahead and finish the passage “ I just want you to notice how much extra time you need. Then come back here.
Okay, are you ready? Let’s do this!
Which type of RC passage is your favorite “ social science, business, hard science? Just kidding! I know that most people don’t have a favorite type (though most of us have a least favorite type).
Let’s try one out. Because of space constraints, I’m not going to give you the full passage, but I promise I’ll give you everything you need to know in order to answer the question. This problem is from the free set of questions that comes with GMATPrep. Give yourself up to 1.5 minutes to read the passage excerpt and approximately another 1.5 minutes to answer the question.
* The modern multinational corporation is described as having originated when the owner-managers of nineteenth-century British firms carrying on international trade were replaced by teams of salaried managers organized into hierarchies. Increases in the volume of transactions in such firms are commonly believed to have necessitated this structural change. Nineteenth-century inventions like the steamship and the telegraph, by facilitating coordination of managerial activities, are described as key factors. Sixteenth- and seventeenth-century chartered trading companies, despite the international scope of their activities, are usually considered irrelevant to this discussion: the volume of their transactions is assumed to have been too low and the communications and transport of their day too primitive to make comparisons with modern multinationals interesting.
In reality, however, early trading companies successfully purchased and outfitted ships, built and operated offices and warehouses, manufactured trade goods for use abroad, maintained trading posts and production facilities overseas, procured goods for import, and sold those goods both at home and in other countries. The large volume of transactions associated with these activities seems to have necessitated hierarchical management structures well before the advent of modern communications and transportation. For example (I’m going to stop you here! There are two more long sentences in this paragraph plus a third paragraph.)
Here’s the question:
The author lists the various activities of early chartered trading companies in order to
(A) analyze the various ways in which these activities contributed to changes in management structure in such companies
(B) demonstrate that the volume of business transactions of such companies exceeded that of earlier firms
(C) refute the view that the volume of business undertaken by such companies was relatively low
(D) emphasize the international scope of these companies’ operations
(E) support the argument that such firms coordinated such activities by using available means of communication and transport
Got your answer? Debating between two answers? Pick! The clock is ticking J
Let’s start with the passage. What did you get out of it? Here are my notes (as far as we read):
P1: MMC: 19c Brit int’l hierarch b/c of >> vol
16-17c: low vol, prim
P2: BUT 16-17 Cos did lots of stuff, >> vol
Note: at this point, while reading the second sentence of paragraph 2, I realized that the first paragraph was some other people theory “ that this hierarchy and MMC thing started in the 19th century “ but the author is disagreeing in the second paragraph. So now I have the author’s overall point and I’m going to add a couple of things to my already-written notes, like this:
P1: HYP: MMC: 19c Brit int’l hierarch b/c of >> vol
As: 16-17c: low vol, prim
P2: BUT 16-17 Cos did lots of stuff, >> vol, had hierarch already?
HYP means hypothesis, and As: means assumption coming! Note that I’m not using the word assumption in the same way I would on a critical reasoning problem. In critical reasoning, assumptions are unstated. Here, this assumption actually was stated “ the author is pointing out what some people assume to be true (but the author disagrees!).
Okay, on to our question. The question stem mentions a particular group: early chartered trading companies. Oh no! I didn’t write that down. What should I do?
A student recently asked me to show an example of how I read and take notes on a reading comprehension passage. In this older article, I discussed how to read through an RC passage in general, but I didn’t show an example. If you haven’t already read the older article, read that first; then come back here to see an example.
The passage below is from the ManhattanGMAT CAT database (copyright MG Prep). If you are still using our exams and haven’t yet seen this passage, then you may want to wait until after you’ve seen the passage before you read this article.
As a general rule, we want to spend about 2 to 2.5 minutes on shorter passages and about 2.5 to 3 minutes on longer passages. The below passage is a longer one, so give yourself up to 3 minutes to read and take light notes.
Last week, a student asked me to write an article on finding The Point in a reading comprehension passage “ specifically, what is The Point and how do we find it? I thought it was a great idea; a lot of people struggle with this.
Note: this article doesn’t address how to answer reading comprehension questions; it focuses on the initial read-through in order to understand the main point of the passage. If you do that well, though, then that should help you answer any kind of question.