If you’ve ever read any of my articles, then you know how much I harp on the idea that the GMAT is primarily a test of your business decision-making, or executive reasoning, skills. Sure, there’s a bunch of facts and rules you need to know, but you don’t need to be a math or grammar superstar in order to get a good score on the GMAT (even though I know it feels that way sometimes).

You do, though, have to be a GMAT master. Business schools want to know that you are going to be a good executive. You can assess a situation rapidly, noticing positive and negative factors that may affect how you want to move forward in that situation. You make appropriate decisions most of the time and you follow through: if you decide that a particular product line needs to be cut, you make that cut. You don’t dribble in another million dollars because you’re reluctant to let go. In short, you can manage your scarce resources (time, money, people) masterfully.

The GMAT is the same game, though your scarce resources on the test are time and mental energy. As such, it is crucial to approach the test as a series of business decisions, not a school test.

How do you take the test with a business mindset? Glad you asked! Read on. Read more

Manhattan Prep GMAT Instructor Jonathan Schneider explains some of the most common mistakes he sees students make when studying for the GMAT.

Be sure to check back every Tuesday for a new video in our GMAT 101 series, detailing the answers to some of the most frequently asked questions about the GMAT.

Recently, we took a look at a story problem dealing with ratios, and I finished up by giving you a second problem to test your skills. How did you do?

If you haven’t already, try the GMATPrep® problem below and then we’ll talk about it. Give yourself about 2 minutes. Go! Read more

You’ve heard a million times that you’re supposed to create Official Guide (OG) problem sets in order to practice for the test. But how do you actually do so in a way that will help you get the most out of your study?

Fear not! This article is coming to your rescue.

Initially, when you’re studying a new topic or problem type, you won’t do sets of problems; instead, you’ll just try one problem at a time. As you gain experience, though, you’re going to want to do 3 problems in a row, or 5, or 10.

Why?

Because the real test will never give you just one problem!

The GMAT will give you many questions in a row and they’ll be all jumbled up—an SC, then a couple of CRs, then back to another SC (that tests different grammar rules than the first one), and so on.

You want to practice two things:

(1) Jumping around among question types and topics

(2) Managing your timing and mental energy among a group of questions

When do I start doing problem sets?

You’re going to use problem sets to test your skills, so you’ve got to develop some of those skills first. If you’re using our Strategy Guides to study, then at the end of one chapter, you’ll do only two or three OG problems to make sure that you understood the material in the chapter.

Later, though, when you finish the Guide, do a set of problems that mix topics (and question types) from that entire book. Make sure you can distinguish between the similar-but-not-quite-the-same topics in that book, and also practice your skills on both problem solving and data sufficiency. As you finish subsequent Guides, your sets can include problems from everything you’ve done so far. Keep mixing it up!

How do I make the sets?

You’ll need to balance three things when you create a problem set:

(1) Number of problems. Initially, start out with about 3 to 5 problems. As you gain experience and add topics, you’ll increase the size of the sets—we’ll talk more about this a little later.

(2) Type of problem and content.
(a) For quant, always do a mix of Problem Solving (PS) and Data Sufficiency (DS). For verbal, mix at least two of the three types; you can include all three types in larger sets.
(b) Do not do a set of 3 or more questions all from the same chapter or content area—for example, don’t do 3 exponents questions in a row. You know exactly what you’re about to get and the real test will never be this nice to you.

(3) Difficulty level.
(a) Include a mix of easier, medium, and harder questions in your set. For all types except Reading Comprehension, the OG places problems in roughly increasing order of difficulty. On average, aroblem 3 is easier than a problem 50, which is easier than a problem 102. (This does not mean that problem 5 is necessarily harder than problem 3. In general, higher question numbers represent harder questions, but the increase is not linear from problem to problem.)
(b) Note: your personal strengths and weaknesses will affect how you perceive the problems—you might think a lower-numbered problem is hard or a higher-numbered problem is easy. They are… for you! Expect that kind of outcome sometimes.

Timing!

Next, calculate how much time to give yourself to do the problem set.
Read more

My last article discussed the difference between inductive and deductive arguments. Today’s article will focus mostly on the rules of deductive arguments. I promise to nerd out on inductive reasoning in later articles.

Here’s a quick quiz on the difference between inductive and deductive logic: //www.thatquiz.org/tq/previewtest?F/Z/J/V/O3UL1355243858

To review: In a deductively “valid” argument, if all the premises are true, the conclusion must also be true, with 100% certainty. Luckily, on the GMAT, we should usually act as if the premises of an argument are true, especially when the question specifies, “the statements above are true.”

Deductive reasoning shows up most often on inference (aka “draw a conclusion”) questions and “mimic the reasoning” questions, but it often appears on other types of questions, and even on reading comprehension!

On inference questions, the correct answer will usually be deductively valid (or very very strong, inductively). An incorrect answer will be deductively invalid, with some significant probability that it could be false.

What follows are most of the formal rules of deductive reasoning (from a stack of logic textbooks I have on my shelf), with examples from the GMAT. For shorthand, I’ll label the arguments with a “P” for premise and a “C” for conclusion:

P) premise
P) premise
C) conclusion

Remember: these are not the same kind of conclusions (opinions) you’ll see on strengthen and weaken questions. Deductive conclusions are deductively “valid” facts that you can derive with 100% certainty from given premises.

EASY STUFF: Simplification/conjunction (“and” statements)

This is kind of a “duh” conclusion, but here goes: If two things are linked with an “and,” then you know each of them exist. Conversely, if two things exist, you can link them with an “and.”

Simplification:

P) A and B
C) Therefore, A

Conjunction:

P) A
P) B
C) Therefore, A and B

P) Bill is tall and was born in Texas.
P) Bill rides a motorcycle.
C) Therefore, Bill was born in Texas (simplification).
C) Therefore, at least one tall person named Bill was born in Texas and rides a motorcycle (conjunction).

CAUTION: Fallacies ahead!!

Don’t confuse “and” with “or.” (More about this later.) More importantly, don’t confuse “and” with causality, condition, or representativeness. Bill’s tallness probably has nothing to do with Texas, so keep an eye out for wrong answers that say, “Bill is tall because he was born in Texas” or “Most people from Texas ride motorcycles.”

MEDIUM STUFF: Disjunctive syllogism (“or” statements)

With “or” statements, if one thing is missing, the other must be true.

Valid conclusions:

P) A or B
P) not B (shorthand: ~B)
C) Therefore, A

P) We will go to the truck rally or to a Shakespeare play
P) We won’t go to the Shakespeare play.
C) Therefore, we will go to the truck rally.

CAUTION: Fallacies ahead!!

Unlike in the real world, “or” statements do not always imply mutual exclusivity, unless the argument explicitly says so. For example, in the above arguments, A and B might both be true; we might go to a play and go to the movies. Yes, really. A wrong answer might say “We went to a play, so we won’t go to the movies.” This error is called “affirming the disjunct.”

Invalid:

P) A or B
P) B
C) Not A

GMAT example:

To see this in action, check out your The Official Guide for GMAT Review 13th Edition, by GMAC®*, question 41. This argument opens with an implied “or” statement:

“Installing scrubbers in smokestacks and switching to cleaner-burning fuel are the two methods available to Northern Power…”

The author here incorrectly assumes that by using one method, Northern Power can’t use both methods at the same time. Question 51 does the same thing; discuss it in the comments below?

TOUGH STUFF: Fun with conditional statements

This is important! Keep a sharp eye out for statements that can be expressed conditionally and practice diagramming them. Look for key words such as “if,” “when,” “only,” and “require.”

I use the symbol “–>” to express an if/then relationship, and a “~” to express the word “not.” Use single letters or abbreviations to stand in for your elements.
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We are very excited to announce that our new book, The Official Guide Companion for Sentence Correction, will hit bookshelve today, December 3^rd!

What is the OGSC (for short)?

It’s one of the best GMAT study guides you could have (if we do say so ourselves)!

Here’s the deal: nearly everyone studies from The Official Guide for GMATÒ Review, 13^th Edition (or OG13). This book contains about 900 real GMAT questions that appeared on the exam in the past. OG13 does contain explanations, but those explanations are “textbook” explanations: reading them is like reading a grammar book. The answers are completely accurate but a bit hard to follow if you’re not a grammar teacher (and some of them are hard to follow even when you are a grammar teacher… ahem).

So we decided to remedy that problem by writing our own explanations for every single one of the 159 Sentence Correction problems contained in OG13. We’ll tell you the SC Process for getting through any SC question efficiently and effectively. We’ll also discuss how to eliminate each wrong answer in terms that are easy for students (not just teachers) to understand. The book includes an extra section on sentence structure and a glossary of common grammar terms. Finally, you’ll gain access to our online GMAT Navigator program which lets you track your OG work, time yourself, and view your performance data so that you can better determine your strengths and weaknesses.

Who should use the OGSC?

Are you struggling to improve your SC performance? Do you love studying official problems but hate trying to decipher the sometimes-mystifying official explanations? Do you want to throw your OG13 across the room when you read yet another explanation that says an answer choice is “wordy” or “awkward”?

If something is “awkward,” there is a real reason why—and we explain that specific reason to you so that you can start to pick out similar faulty constructions on other problems in future. (Did you know that, most of the time, “wordy” and “awkward” are code words for an ambiguous or illogical meaning? The OGSC will help you learn how to decipher these for yourself!)

How can I get the most out of the OGSC?

First, read the introduction chapter, where you’ll learn all about how to work through an SC problem in an efficient manner.

Next, if you have already started studying Sentence Correction problems from the OG, begin with the problems that you’ve tried recently. Try to articulate to yourself why each of the four wrong answers is wrong. Try to find all of the errors in each answer (though, on the real test, just one error is enough to eliminate an answer!).

Note: You don’t need to use grammar terminology when you’re trying to articulate why something’s wrong, but do try to go beyond “this one sounds bad.” That’s a good starting point but which part, specifically, sounds bad? What sounds so bad about that part?

Then, check yourself against the explanations. If you didn’t spot a particular error, go back to the problem and ask yourself what clues (in the form of differences in the answer choices) will alert you the next time this particular topic is being tested. If you didn’t know how to handle the issue but now understand from the explanation, make yourself a flashcard to help you remember whatever that is for future. If the explanation seems like Greek to you, then maybe this particular issue is too hard and your take-away is to skip something like this in future and make a guess!

When you’re ready to try new OG problems, make sure to do them under timed conditions (try to average about 1 minute 20 seconds on SC). When you’re done, check the answer. If you guessed, go ahead straight to the explanation. If you got it right, try to articulate why each incorrect answer is wrong, then check the explanation. If you got it wrong, look at the problem again to see whether you might have made a careless mistake. Then go to the explanation.

Where can I get the OGSC?

You can find The Official Guide Companion for Sentence Correction on our website starting today!

Let us know what you think in the Comments section below. Good luck and happy studying!