Articles tagged "graduate management admissions test"

Manhattan Prep secures endorsement from Dr. Lawrence Rudner, leading GMAT authority

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Larry Explains 2I have some very exciting news to announce.

For the past several months, we have engaged Dr. Lawrence Rudner, former Chief Psychometrician of the Graduate Management Admissions Council (GMAC, the makers of the GMAT®), to review our practice tests. Dr. Rudner is one of the world’s leading experts in item response theory, the testing principle on which the GMAT is based. He is the definitive authority on the GMAT examination.

And here’s what he has to say about Manhattan Prep’s practice exams:

“I conducted an extensive examination of student data for all of the Manhattan Prep test questions and I was very impressed. I can attest to the fact that very high percentages of Quant and Verbal items have excellent psychometric properties. I can further attest that Manhattan Prep’s GMAT practice exams do an excellent job of predicting a student’s score on the actual GMAT examination. Manhattan Prep’s GMAT practice exams can help you accurately gauge when you’re ready to achieve your goal score on the real test.”

Lawrence M. Rudner, PhD, MBA

In short, our tests do “an excellent job of predicting” your score on the real GMAT. That’s great news!

I am particularly excited about the fact that our CATs were so strong that Dr. Rudner offered his endorsement without requiring us to change a single thing. Going into the review, we had thought that we would be given a required list of changes before he could give his seal of approval.

I do have to add a caveat: nothing is perfect and not everyone scores on the real test exactly what they scored on our test (or any practice test). No standardized test is that precise, including the real GMAT. There are also other factors that can negatively affect certain students, such as anxiety (you know your practice tests don’t really count) or mental fatigue (don’t study for 6 hours the day before the real exam!).

Caveat over. In general, you can trust our exams to help you know when you’re ready to get in there and take the real thing. I already felt that way before, but now I can say it with conviction, because Dr. Rudner has confirmed the accuracy of our exams.

I have to give a shout-out to all of our instructors who have worked so diligently on our exams over the years—you know who you are. We literally would not be having this conversation right now if not for your hard work and dedication to making our materials the best. Thank you for your love of teaching and your complete fascination with the GMAT. I’m proud to call you colleagues and friends.

And back to our students: Go forth and study! You can beat this test!

GMAT Problem Solving Strategy: Test Cases

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3-19-TestCasesIf you’re going to do a great job on the GMAT, then you’ve got to know how to Test Cases. This strategy will help you on countless quant problems.

This technique is especially useful for Data Sufficiency problems, but you can also use it on some Problem Solving problems, like the GMATPrep® problem below. Give yourself about 2 minutes. Go!

* “For which of the following functions f is f(x) = f(1 – x) for all x?

(A) f(x) = 1 – x
(B) f(x) = 1 – x2
(C) f(x) = x2 – (1 – x)2
(D) f(x) = x2(1 – x)2
(E)  f(x) = x / (1 – x)”

 

Testing Cases is mostly what it sounds like: you will test various possible scenarios in order to narrow down the answer choices until you get to the one right answer. What’s the common characteristic that signals you can use this technique on problem solving?

The most common language will be something like “Which of the following must be true?” (or “could be true”).

The above problem doesn’t have that language, but it does have a variation: you need to find the answer choice for which the given equation is true “for all x,” which is the equivalent of asking for which answer choice the given equation is always, or must be, true.
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How to Switch from the GMAT to the GRE

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2015-03-12_1126Lately, we’ve been talking about how to decide which test to take, as well as what to do if you decide to stick with the GMAT. What if you decide to switch from the GMAT to the GRE? That’s what we’ll tackle today! (Next time, we’ll talk about what to do if you want to switch from the GRE to the GMAT.)

How do I study?

The overall way that you want to study doesn’t actually change that much; rather, you’ll just need to change what you are studying, as discussed later in this article.

First, you’ll need to determine whether the way that you’ve already been studying is actually the optimal way. If not, then you’ll need to make some changes, regardless of whether you stick with the GMAT or switch to the GRE.

The GMAT and the GRE are both executive reasoning tests; that is, the test makers want to know how you think and make decisions. You of course need to know content (certain facts, rules, formulas) in order to do well on either test, but that level of study is not enough; you also need to lift yourself to a second level of understanding that allows you to think your way through these sometimes bizarrely-worded problems as effectively and efficiently as possible.

Follow the two links I put in the last paragraph. Take some time to just think about the concepts presented there. Has this been your approach to studying so far? If so, great. Keep thinking and working in that way.

If not, however, recognize that you’re going to need to start studying with this new mindset, regardless of whether you take the GMAT or the GRE.

What are my strengths and weaknesses?

Any time you’re developing or revising a study plan, you’ll want to put together a solid analysis of your strengths and weaknesses.

If you have been studying for the GMAT for a while, then you should have some practice CAT data. (If not, or if it has been more than 6 weeks since you last took a CAT, then you’ll need to take one to get the data. Make sure to take the test under official conditions, including the essay and IR sections, length of breaks, and so on.)
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Should I re-take the GMAT? If so, how?

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3-3-RetakeGMATSo you’ve taken the test and you aren’t entirely happy with your score. How do you decide whether to re-take the test?

It might be the case that your score is close to what you wanted, but not quite all the way there. Alternatively, you may be trying to decide whether to stick with the GMAT or switch to the GRE (and, if so, I recommend you follow that link I just inserted).

If you already know that you do want to stick with the GMAT, read on.

Should I re-take?

There are two main reasons someone might want to go for a higher score. The most common is that you think a better score will improve your chances of getting into business school or of obtaining certain internships once in school. Some people also feel that achieving a certain score is a personal goal and they want to meet that challenge.

If you’re trying to gauge whether a better score will make a big difference, start researching. What’s the average or median score for last year’s incoming class at your preferred schools? (Look at whatever data the school publishes—different schools might publish data in different forms.) Are you in range? Are you strong? If you are already above the average or median at that school, then adding 30 points might not make as big a difference as, say, earning a promotion at work.

Check GPA statistics as well. You have a little leeway for your GMAT score to be lower if your GPA is higher than the average for admitted students; if your GPA is lower, however, then it would be better to have an above-average GMAT. (Also, all of this just means that you have a chance, not that you’ll definitely get in. These are only two of many parts to your application!)
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Should I take the GMAT or the GRE?

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3-2-WhichTest-GMATMost business schools now accept both the GMAT and the GRE, so which one should you take? I’ve written on the topic before but it’s been nearly a year and I’ve got some updates.

The conventional wisdom has been that the math is easier on the GRE. Though many schools do accept the GRE, rumors abound that students who take this test are at a bit of a disadvantage because they are expected to do better on the (easier) quant section. Anecdotally, we have heard a few admissions officers admit that they do think about this (strictly off the record, of course). Most admissions officers, though, have said this doesn’t matter to them at all, including several officers at the top 10 schools.

So we’ve come up with a series of decisions to help you make this choice. The first three questions are “deal-breakers”—that is, a certain answer will point you definitively to a specific test (the GMAT, as it happens). The fourth question is…murkier. We’ll address that in a little bit.

#1: Do all of “your” schools accept the GRE?

This one is obvious. All business schools (that ask for a standardized test score) accept the GMAT. Most—but not all—accept the GRE. If you want to apply to any schools that require the GMAT, such as London Business School MBA (at the time of this publication), then you’ll be taking the GMAT.

#2: Do any of “your” schools prefer the GMAT?

Most schools that accept both tests don’t express a preference between the two. Some schools, though, do say that the prefer the test. They publish this preference right on their web site, so go look up all of your schools and see what they say about the GMAT / GRE requirement for admissions.

As of the date of this article, Columbia, Haas (Berkeley) and Anderson (UCLA) all state that they prefer the GMAT, even though they do accept the GRE. If you want to apply to one of these schools, I recommend that you take the GMAT. (Note: these aren’t the only three schools that prefer the GMAT; I just picked out the three most well-known ones that do. You still need to research your schools!)

#3: Do you want to go into banking or management consulting after b-school?

The major banks and consulting firms ask for GMAT scores when you apply. (Some of them even ask for undergraduate GPA and SAT scores. I think that data is irrelevant after someone has a b-school GPA and GMAT scores but I’m not the one making the hiring decisions!)
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Break Your “Good” GMAT Study Habits! What Learning Science Can Teach Us About Effective GMAT Studying

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2-6-HabitsDistractions are bad. Routine, concentration, and hard work are good. These all seem like common-sense rules for studying, right? Surprisingly (for many people, at least), learning science tells us that these “good habits” may actually be hurting your learning process!

When you were in college, your study process probably looked something like this: for a given class, you’d attend a lecture each week, do the readings (or at least most of them), and maybe turn in an assignment or problem set. Then, at the end of the semester, you’d spend a week furiously cramming all of that information to prepare for the test.

Since this is the way you’ve always studied, it’s probably how you’re approaching the GMAT, too. But I have bad news: this is not an effective approach for the GMAT!

Taking notes then cramming the night before the test is beneficial for tests that ask you to recite knowledge: “what were the major consequences of the Hawley-Smoot tariff” or “explain Heisenberg’s uncertainty principle.” You can hold a lot of facts  -for a brief time – in your short-term memory when cramming. You memorize facts, you spit them out for the test… and then, if you’re like me, you find that you’ve forgotten half of what you memorized by the next semester.

Why the GMAT is Different

The GMAT doesn’t reward this style of studying because it’s not simply a test of facts or knowledge. The GMAT requires you to know a lot of rules, of course, but the main thing that it’s testing is your ability to apply those concepts to new problems, to adapt familiar patterns, and to use strategic decision-making. You’ll never see the same problem twice.

Shallow memorization is not nearly enough. You need deep conceptual understanding.

In How We Learn*, science writer Benedict Carey outlines decades of research about how this kind of learning happens. Many of the findings go against what you probably thought were “good” study habits.
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GMAT Sentence Correction: How To Find the Core Sentence (Part 4)

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introIt’s here at last: the fourth and final installment of our series on core sentence structure! I recommend reading all of the installments in order, starting with part 1.

Try out this GMATPrep® problem from the free exams.

* “The greatest road system built in the Americas prior to the arrival of Christopher Columbus was the Incan highway, which, over 2,500 miles long and extending from northern Ecuador through Peru to southern Chile.

“(A) Columbus was the Incan highway, which, over 2,500 miles long and extending

“(B) Columbus was the Incan highway, over 2,500 miles in length, and extended

“(C) Columbus, the Incan highway, which was over 2,500 miles in length and extended

“(D) Columbus, the Incan highway, being over 2,500 miles in length, was extended

“(E) Columbus, the Incan highway, was over 2,500 miles long, extending”

The First Glance in this question is similar to the one from the second problem in the series. Here, the first two answers start with a noun and verb, but the next three insert a comma after the subject. Once again, this is a clue to check the core subject-verb sentence structure.

First, strip down the original sentence:

gmat

Here’s the core:

The greatest road system was the Incan highway.

(Technically, greatest is a modifier, but I’m leaving it in because it conveys important meaning. We’re not just talking about any road system. We’re talking about the greatest one in a certain era.)

The noun at the beginning of the underline, Columbus, is not the subject of the sentence but the verb was does turn out to be the main verb in the sentence. The First Glance revealed that some answers removed that verb, so check the remaining cores.

“(B) The greatest road system was the Incan highway and extended from Ecuador to Chile.

“(C) The greatest road system.

“(D) The greatest road system was extended from Ecuador to Chile.

“(E) The greatest road system was over 2,500 miles long.”

Answer (C) is a sentence fragment; it doesn’t contain a main verb. The other choices do contain valid core sentences, though answers (B) and (D) have funny meanings. Let’s tackle (B) first.

“(B) The greatest road system was the Incan highway and extended from Ecuador to Chile.

When two parts of a sentence are connected by the word and, those two parallel pieces of information are not required to have a direct connection:

Yesterday, I worked for 8 hours and had dinner with my family.

Those things did not happen simultaneously. One did not lead to the other. They are both things that I did yesterday, but other than that, they don’t have anything to do with each other.

In the Columbus sentence, though, it doesn’t make sense for the two pieces of information to be separated in this way. The road system was the greatest system built to that point in time because it was so long. The fact that it extended across all of these countries is part of the point. As a result, we don’t want to present these as separate facts that have nothing to do with each other. Eliminate answer (B).
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What is the GMAT? An Introduction to the GMAT Exam

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The Graduate Management Admission Test, better known as the GMAT®, is a standardized test used in the admissions process for business school and other specialized Master’s programs. The exam measures certain skills that the business schools care about, most notably Executive Reasoning skills. It does not test any specific business knowledge.

When is the GMAT given?

You can take the GMAT year-round, nearly any day of the week (though they limit you to 5 sittings in a 12-month period and require a wait of 31 days between tests). The exam is given on a computer and is known as a “CAT.”

What is a CAT?

A CAT is a computer-adaptive test: the test actually adapts itself to you while you’re taking it! Two of the four sections on the GMAT, the Quantitative and Verbal sections, are adaptive. Each of these two sections begins with a random, approximately medium-level question. The computer chooses each subsequent question based upon your collective performance to that point in the section.

The practical implications are important. First, every test taker will take a different exam with a different mix of questions, but the test feels hard for everyone, since the test will just keep getting harder until it finds a particular person’s limit. Second, the scoring is pretty peculiar; it’s important to understand how the scoring works.

Want to try your hand at a practice test? Take our free, full-length practice exam here.

How is the GMAT Scored?

Tests you took in school were generally based on the percentage of questions answered correctly: the more you got right, the higher the score you received. As a result, you have been trained to take your time and try to get everything right when you take a test. This general strategy does not work on computer-adaptive sections of the GMAT because, strangely enough, the quant and verbal scores are not based on the percentage of questions answered correctly. On the GMAT, most people answer similar percentages of questions correctly, typically in the 50% to 70% range (even at higher scoring levels!).

How is that possible? The first thing to know: the GMAT is not a school test. The quant section is not really a math test, and the verbal section is not really a grammar test. Of course, you do need to know how to handle those topics. The test writers are really interested, however, in knowing how good you are at making decisions and managing scarce resources. (That’s the second time we’ve linked to that same article. Go read it!)
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GMAT Sentence Correction: How To Find the Core Sentence (Part 3)

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1-9-SC-PIIIWelcome to the third installment of our Core Sentence series. In part 1, we began learning how to strip an SC sentence (or any sentence!) down to the core sentence structure. In part 2, we took a look at a compound sentence structure.

Today, we’re going to look at yet another interesting sentence structure that is commonly used on the GMAT.

Try out this GMATPrep® problem from the free exams. (Note: as in the previous installments, I’m going to discuss aspects of our SC Process; if you haven’t learned it already, read about it before doing this problem.)

* “Many financial experts believe that policy makers at the Federal Reserve, now viewing the economy as balanced between moderate growth and low inflation, are almost certain to leave interest rates unchanged for the foreseeable future.

“(A) Reserve, now viewing the economy as balanced between moderate growth and low inflation, are

“(B) Reserve, now viewing the economy to be balanced between that of moderate growth and low inflation and are

“(C) Reserve who, now viewing the economy as balanced between moderate growth and low inflation, are

“(D) Reserve, who now view the economy to be balanced between that of moderate growth and low inflation, will be

“(E) Reserve, which now views the economy to be balanced between moderate growth and low inflation, is”

The First Glance didn’t tell me a lot on this one. In each case, there appears to be some kind of modifier going on, signaled either by the who / which language or by the comma, but I don’t have a good idea of what’s being tested. Time to read the sentence.

I don’t know about you, but the original sentence really doesn’t sound good to me. The difficulty, though, is that I don’t know exactly why. I just find myself thinking, “Ugh, I wouldn’t say it that way.”

Specifically, I don’t like the “now viewing” after the comma…but when I examined it a second time, I couldn’t find an actual error. That’s a good clue to me that I need to leave the answer in; they’re just trying to fool my ear (and almost succeeding!).

Because I’m not certain what to examine and because I know that there may be something going on with modifiers, I’m going to strip the original sentence down to the core:

gmat

Here’s the core:

Many experts believe that policy makers are almost certain to leave interest rates unchanged.

This sentence uses what we call a “Subject-Verb-THAT” structure. When you see the word that immediately after a verb, expect another subject and verb (and possibly object) to come after. The full core will be Subject-Verb-THAT-Subject-Verb(-Object).

gmat

Back to the problem: notice where the underline falls. The Subject-Verb-THAT-Subject part is not underlined, but the second verb is, and it’s the last underlined word. Check the core sentence with the different options in the answers:

Many experts believe that policy makers __________ almost certain to leave rates unchanged.

(A) Many experts believe that policy makers are almost certain to leave rates unchanged.

(B) Many experts believe that policy makers and are almost certain to leave rates unchanged.

(C) Many experts believe that policy makers.

(D) Many experts believe that policy makers will be almost certain to leave rates unchanged.

(E) Many experts believe that policy makers is almost certain to leave rates unchanged.

Excellent! First, answer (E) is wrong because it uses a singular verb to match with the plural policy makers.

Next, notice that answer (B) tosses the conjunction and into the mix. A sentence can have two verbs, in which case you could connect them with an and, but this answer just tosses in a random and between the subject and the verb. Answer (B) is also incorrect.

Answer (C) is tricky! At first, it might look like the core is the same as answer (A)’s core. It’s not. Notice the lack of a comma before the word who. Take a look at this example:

The cat thought that the dog who lived next door was really annoying.

What’s the core sentence here? This still has a subject-verb-THAT-subject-verb(-object) set-up. It also has a modifier that contains its own verb—but this verb is not part of the core sentence:

The cat thought that the dog [who lived next door] was really annoying.

Answer (C) has this same structure:

Many experts believe that policy makers [who are almost certain to leave rates unchanged]…

Where’s the main verb that goes with policy makers? It isn’t there at all. Answer (C) is a sentence fragment.

We’re down to answers (A) and (D). Both cores are solid, so we’ll have to dig a little deeper. So far, we’ve been ignoring the modifier in the middle of the sentence. Let’s take a look; compare the two answers directly:

“(A) Reserve, now viewing the economy as balanced between moderate growth and low inflation, are

“(D) Reserve, who now view the economy to be balanced between that of moderate growth and low inflation, will be”

Probably the most obvious difference is are vs. will be. I don’t like this one though because I think either tense can logically finish the sentence. I’m going to look for something else.

There are two other big differences. First, there’s an idiom. Is it view as or view to be? If you’re not sure, there’s also a comparison issue. Is the economy balanced between growth and inflation? Or between that of growth and inflation?

The that of structure should be referring to another noun somewhere else: She likes her brother’s house more than she likes that of her sister. In this case, that of refers to house.

What does that of refer to in answer (D)?

I’m not really sure. The economy? The Federal Reserve? These don’t make sense. The two things that are balanced are, in fact, the growth and the inflation; that of is unnecessary. Answer (D) is incorrect.

The correct answer is (A).

The correct idiom is view as, so answers (B), (D), and (E) are all incorrect based on the idiom.

Key Takeaways: Strip the sentence to the Core

(1) When you see the word that immediately following a verb, then you have a Subject-Verb-THAT-Subject-Verb(-Object) structure. Check the core sentence to make sure that all of the necessary pieces are present. Also make sure, as always, that the subjects and verbs match.

(2) If you still have two or more answers left after dealing with the core sentence, then check any modifiers. The two main modifier issues are bad placement (which makes them seem to be pointing to the wrong thing) or meaning issues. In this case, the modifier tossed in a couple of extraneous words that messed up the meaning of the between X and Y idiom.

* GMATPrep® questions courtesy of the Graduate Management Admissions Council. Usage of this question does not imply endorsement by GMAC.

GMAT Sentence Correction: How To Find the Core Sentence (Part 1)

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modifierRecently, I was discussing sentence structure with one of my classes and we practiced a crucial but difficult GMAT skill: how to strip an SC sentence to its core components. Multiple OG problems can be solved just by eliminating faulty sentence cores—and the real GMAT is testing this skill today more than we see in the published materials.

So I’m going to write a series of articles on just this topic; welcome to part 1 (and props to my Wednesday evening GMAT Fall AA class for inspiring this series!).

Try out this GMATPrep® problem from the free exams. (Note: in the solution, I’m going to discuss aspects of our SC Process; if you haven’t learned it already, go read about it right now, then come back and try this problem.)

* “With surface temperatures estimated at minus 230 degrees Fahrenheit, Jupiter’s moon Europa has long been considered far too cold to support life, and with 60 square miles of water thought to be frozen from top to bottom.

“(A) Europa has long been considered far too cold to support life, and with

“(B) Europa has long been considered far too cold to support life, its

“(C) Europa has long been considered as far too cold to support life and has

“(D) Europa, long considered as far too cold to support life, and its

“(E) Europa, long considered to be far too cold to support life, and to have”

The First Glance does help on this one, but only if you have studied sentence structure explicitly. Before I did so, I used to think: “Oh, they started with Europa because they added a comma in some answers, but that doesn’t really tell me anything.”

But I’ve learned better! What is that comma replacing? Check it out: the first three answers all have a verb following Europa. The final two don’t; that is, the verb disappears. That immediately makes me suspect sentence structure, because a sentence does have to have a verb. If you remove the main verb from one location, you have to put one in someplace else. I’ll be watching out for that when I read the sentence.

And now it’s time to do just that. As I read the sentence, I strip it down to what we call the “sentence core” in my mind. It took me a long time to develop this skill. I’ll show you the result, first, and then I’ll tell you how I learned to do it.

The “sentence core” refers to the stuff that has to be there in order to have a complete sentence. Everything else is “extra”: it may be important later, but right now, I’m ignoring it.

modifier

I greyed out the portions that are not part of the core. How does the sentence look to you?

Notice something weird: I didn’t just strip it down to a completely correct sentence. There’s something wrong with the core. In other words, the goal is not to create a correct sentence; rather, you’re using certain rules to strip to the core even when that core is incorrect.

Using this skill requires you to develop two abilities: the ability to tell what is core vs. extra and the ability to keep things that are wrong, despite the fact that they’ll make your core sound funny. The core of the sentence above is:

Europa has long been considered too cold to support life, and.

Clearly, that’s not a good sentence! So why did I strip out what I stripped out, and yet leave that “comma and” in there? Here was my thought process:

Text of sentence My thoughts:
“With…” Preposition. Introduces a modifier. Can’t be the core.
With surface temperatures estimated at minus 230 degrees Fahrenheit,” Each word I’ve italicized introduces a new noun modifier. Nothing here is a subject or main verb. *
“Jupiter’s moon Europa” The main noun is Europa; ignore the earlier words.
“Europa has long been considered far too cold to support life,” That’s a complete sentence. Yay.
“, and” A complete sentence followed by “comma and”? I’m expecting another complete sentence to follow. **
with 60 square miles of water thought to be frozen from top to bottom.” Same deal as the beginning of the sentence! Each word I’ve italicized introduces a new modifier. Nothing here that can function as a subject or main verb.

 

* Why isn’t estimated a verb?

Estimated is a past participle and can be part of a verb form, but you can’t say “Temperatures estimated at minus 230 degrees Fahrenheit.” You’d have to say “Temperatures are estimated at…” (Note: you could say “She estimated her commute to be 45 minutes from door to door.” In other words, estimated by itself can be the main verb of a sentence. In my example, though, the subject is actually doing the estimating. In the GMATPrep problem above, the temperatures can’t estimate anything!)

** Why is it that I expected another complete sentence to follow the “comma and”?

The word and is a parallelism marker; it signals that two parts of the sentence need to be made parallel. When you have one complete sentence, and you follow that with “comma and,” you need to set up another complete sentence to be parallel to that first complete sentence.

For example:

She studied all day, and she went to dinner with friends that night.

The portion before the and is a complete sentence, as is the portion after the and.

(Note: the word and can connect other things besides two complete sentences. It can connect other segments of a sentence as well, such as: She likes to eat pizza, pasta, and steak. In this case, although there is a “comma and” in the sentence, the part before the comma is not a complete sentence by itself. Rather, it is the start of a list.)

Okay, so my core is:

Europa has long been considered too cold to support life, and.

And that’s incorrect. Eliminate answer (A). Either that and needs to go away or, if it stays, I need to have a second complete sentence. Since you know the sentence core is at issue here, check the cores using the other answer choices:

modifier

Here are the cores written out:

“(B) Europa has long been considered too cold to support life.

“(C) Europa has long been considered as too cold to support life and has 60 square miles of water.

“(D) Europa and its 60 square miles of water.

“(E) Europa.”

(On the real test, you wouldn’t have time to write that out, but you may want to in practice in order to build expertise with this technique.)

Answers (D) and (E) don’t even have main verbs! Eliminate both. Answers (B) and (C) both contain complete sentences, but there’s something else wrong with one of them. Did you spot it?

The correct idiom is consider X Y: I consider her intelligent. There are some rare circumstances in which you can use consider as, but on the GMAT, go with consider X Y. Answers (C), (D), and (E) all use incorrect forms of the idiom.

Answer (C) also loses some meaning. The second piece of information, about the water, is meant to emphasize the fact that the moon is very cold. When you separate the two pieces of information with an and, however, they appear to be unrelated (except that they’re both facts about Europa): the moon is too cold to support life and, by the way, it also has a lot of frozen water. Still, that’s something of a judgment call; the idiom is definitive.

The correct answer is (B).

Go get some practice with this and join me next time, when we’ll try another GMATPrep problem and talk about some additional aspects of this technique.

Key Takeaways: Strip the sentence to the Core

(1) Generally, this is a process of elimination: you’re removing the things that cannot be part of the core sentence. With rare exceptions, prepositional phrases typically aren’t part of the core. I left the prepositional phrase of water in answers (C) and (D) because 60 square miles by itself doesn’t make any sense. In any case, prepositional phrases never contain the subject of the sentence.

(2) Other non-core-sentence clues: phrases or clauses set off by two commas, relative pronouns such as which and who, comma + -ed or comma + ing modifiers, -ed or –ing words that cannot function as the main verb (try them in a simple sentence with the same subject from the SC problem, as I did with temperatures estimated…)

(3) A complete sentence on the GMAT must have a subject and a working verb, at a minimum. You may have multiple subjects or working verbs. You could also have two complete sentences connected by a comma and conjunction (such as comma and) or a semi-colon. We’ll talk about some additional complete sentence structures next time.

* GMATPrep® questions courtesy of the Graduate Management Admissions Council. Usage of this question does not imply endorsement by GMAC.