“I’m Bad at Memorization” and Other Lies You Tell Yourself

Did you know that your ability to memorize and recall information is not only a skill, but also an improvable one? Most people are born with approximately the same ability to memorize information. If you’re fluent in a language, any language, you’ve memorized at least tens of thousands of words that you can instantly recall and use. So why is it so hard to remember what the cube of five is? Or to remember that before you start reading a sentence correction sentence, you should take a glance first at the answer choices?

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I know this is a totally unnecessary article, since I’m sure you enjoy taking the GMAT very much already. But do keep reading: at the very least, you’ll have a new way of explaining to your friends why you’re spending all your weeknights curled up with a gently used copy of the test’s Official Guide.

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You’ve studied, and studied, and studied, and studied. You can rattle off the first twenty perfect squares and the definition of a dependent clause. You know the four-step process for Critical Reasoning and the formula for the volume of a cylinder. So, why are you still missing GMAT problems?

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A quick note: this is a pretty deep dive into a single GMAT Critical Reasoning question type. If you’re just beginning to learn CR strategy, check out The GMAT Critical Reasoning Mindset or How to Master Every GMAT Critical Reasoning Question Type

Inference questions are not super common on GMAT Critical Reasoning, usually only accounting for 1 of your 10 CR questions. However, it tends to be a question type that students miss more frequently, in both CR and Reading Comprehension. Some of this stems from the inherent difficulty, but much of it can result from students’ possessing an incorrect or incomplete sense of what they’re supposed to be doing on these problems.

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Did you know that you can attend the first session of any of our online or in-person GMAT courses absolutely free? We’re not kidding! Check out our upcoming courses here.

Have you ever heard the saying “measure twice, cut once”? Read more

Did you know that you can attend the first session of any of our online or in-person GMAT courses absolutely free? We’re not kidding! Check out our upcoming courses here.

If you read the first post in this series, then you already know how to get the most you can out of the first 5 seconds of a GMAT Quant problem. But what about the other 1:55? Let’s continue to delve. Read more

Did you know that you can attend the first session of any of our online or in-person GMAT courses absolutely free? We’re not kidding! Check out our upcoming courses here.

Two minutes is not a huge amount of time. Yet if you want to finish the entire GMAT Quant section in 75 minutes, two minutes is about all you have to solve each problem. Don’t interpret that to mean you just have to go quickly or skip important steps like checking your work. Instead, seek out a more efficient process for dealing with GMAT problems.

Better yet, read along as I detail an efficient process for dealing with your two minutes. Read more

You’re staring at a GMAT problem that you just don’t understand. There’s a minute left on the clock. What do you do? Read more

As dedicated readers of this blog may have guessed, this is a follow up to my earlier post When is it Time to Guess on Quant? Timing troubles are not, however, exclusive to the Quant section, so in this piece I’ll talk about some common scenarios that bedevil students on the Verbal section.

As with Quant, not all guesses are created equal. The earlier you decide to guess, the more likely that you will make a random guess. If, on the other hand, you’re far enough into the question that you’ve eliminated 2-3 answer choices, then you’ll be making an educated guess.

One immediate difference between guessing on Quant and Verbal is that guessing strategy is essentially identical for both Problem Solving and Data Sufficiency questions. Each of the Verbal question types, on the other hand, has less in common. That being said, there are a lot of parallels in guessing strategy among the three types.

No matter the question, there are really three distinct stages at which it becomes a better idea to guess than to keep going. I’ll briefly describe each stage, then show how it connects to each of the Verbal question types.

Stage 1: No Clear Starting Point

As a general rule, if you haven’t really made progress on a question after 30 seconds or so, it’s usually a good idea to just make a random guess and save your energy for a question you’re more comfortable with.

Reading Comprehension Stage 1: I don’t know where in the passage to look.

The great thing about Reading Comprehension (or at least its saving grace) is that the correct answer has to have support in the passage. With the vast majority of RC questions, as long as you can find and reread the relevant portion of the passage, you can find an answer choice that will match what you read. In fact, you should be able to answer to come up with your own answer to most RC questions before you even look at the answer choices.

Many questions provide good clues as to where in the passage to look for the answer (seriously – a surprising amount of questions are very helpful in that regard). Things get much tougher when they don’t. So here’s your first big clue that it may be time to guess. If you’ve read the question, and you’ve skimmed through the passage looking for an answer, and you still don’t feel like you found what the question was asking about, it’s time to guess.

At this point, you could guess randomly, but I would recommend taking one quick pass through the answer choices. If any choice contradicts your understanding of the passage, eliminate it. After you’ve each answer once, pick from the remaining.

Sentence Correction Stage 1: I don’t understand the sentence and the underline is long.

On the Verbal section, you have to answer 41 questions in 75 minutes, which is less than 2 minutes per question. Critical Reasoning and Reading Comprehension are naturally time-consuming, so that time is going to have be saved largely on Sentence Correction. Remember that you only have an average of 1 minute and 20 seconds to answer these things.

If you’re struggling to even understand what the sentence is saying, then it will almost certainly take too long to properly analyze the answer choices, especially if the underline is long. No need to fight through the pain. Just take a quick scan through the answer choices and pick one that doesn’t sound immediately wrong.

Critical Reasoning Stage 1: I don’t understand what the argument is saying.

To my mind, good process on Critical Reasoning questions means being in control the whole way through the process. The worst situation to be in is one in which you’re hoping that the answer choices will help you make sense of the argument. Four out of the five answer choices are actively trying to trick you, and the GMAT has gotten pretty good at tricking people over the years. By the time you get to the answer choices, you need to understand the argument well enough to effectively evaluate each choice.

Consequently, if you’ve read the argument two or three times, and still can’t articulate to yourself the link between the premises and the conclusion, you shouldn’t waste time with the answer choices.

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A while back, we talked about the 4 GMAT math strategies that everyone needs to master. Today, I’ve got some additional practice for you with regard to one of those strategies: Testing Cases.

Try this GMATPrep® problem:

* ” If xy + z = x(y + z), which of the following must be true?

“(A) x = 0 and z = 0

“(B) x = 1 and y = 1

“(C) y = 1 and z = 0

“(D) x = 1 or y = 0

“(E) x = 1 or z = 0

How did it go?

This question is called a “theory” question: there are just variables, no real numbers, and the answer depends on some characteristic of a category of numbers, not a specific number or set of numbers. Problem solving theory questions also usually ask what must or could be true (or what must not be true). When we have these kinds of questions, we can use theory to solve—but that can get very confusing very quickly. Testing real numbers to “prove” the theory to yourself will make the work easier.

The question stem contains a given equation:

xy + z = x(y + z)

Whenever the problem gives you a complicated equation, make your life easier: try to simplify the equation before you do any more work.

xy + z = x(y + z)

xy + z = xy + xz

z =  xz

Very interesting! The y term subtracts completely out of the equation. What is the significance of that piece of info?

Nothing absolutely has to be true about the variable y. Glance at your answers. You can cross off (B), (C), and (D) right now!

Next, notice something. I stopped at z = xz. I didn’t divide both sides by z. Why?

In general, never divide by a variable unless you know that the variable does not equal zero. Dividing by zero is an “illegal” move in algebra—and it will cause you to lose a possible solution to the equation, increasing your chances of answering the problem incorrectly.

The best way to finish off this problem is to test possible cases. Notice a couple of things about the answers. First, they give you very specific possibilities to test; you don’t even have to come up with your own numbers to try. Second, answer (A) says that both pieces must be true (“and”) while answer (E) says “or.” Keep that in mind while working through the rest of the problem.

z =  xz

Let’s see. z = 0 would make this equation true, so that is one possibility. This shows up in both remaining answers.

If x = 0, then the right-hand side would become 0. In that case, z would also have to be 0 in order for the equation to be true. That matches answer (A).

If x = 1, then it doesn’t matter what z is; the equation will still be true. That matches answer (E).

Wait a second—what’s going on? Both answers can’t be correct.

Be careful about how you test cases. The question asks what MUST be true. Go back to the starting point that worked for both answers: z = 0.

It’s true that, for example, 0 = (3)(0).

Does z always have to equal 0? Can you come up with a case where z does not equal 0 but the equation is still true?

Try 2 = (1)(2). In this case, z = 2 and x = 1, and the equation is true. Here’s the key to the “and” vs. “or” language. If z = 0, then the equation is always 0 = 0, but if not, then x must be 1; in that case, the equation is z = z. In other words, either x = 1 OR z = 0.

The correct answer is (E).

The above reasoning also proves why answer (A) could be true but doesn’t always have to be true. If both variables are 0, then the equation works, but other combinations are also possible, such as z = 2 and x = 1.

Key Takeaways: Test Cases on Theory Problems

(1) If you didn’t simplify the original equation, and so didn’t know that y didn’t matter, then you still could’ve tested real numbers to narrow down the answers, but it would’ve taken longer. Whenever possible, simplify the given information to make your work easier.

(2) Must Be True problems are usually theory problems. Test some real numbers to help yourself understand the theory and knock out answers. Where possible, use the answer choices to help you decide what to test.

(3) Be careful about how you test those cases! On a must be true question, some or all of the wrong answers could be true some of the time; you’ll need to figure out how to test the cases in such a way that you figure out what must be true all the time, not just what could be true.

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