“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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If your goal is to take some time pressure off of the quantitative section of the GMAT, you should ask yourself: what are the skills I will need over and over during that section, and what are the skills I will only need once or twice? Too often I see my own students spending hours to get incrementally faster at, for example, weighted averages; that’s an area where understanding the basic concept is probably sufficient. Instead, invest the most time in the thing you’ll be doing the most often: calculation! 

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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.

Sometimes, as you solve a GMAT Problem Solving problem, everything seems to go smoothly. You get an answer that matches one of the choices perfectly, so you select it and move on to the next problem. But much later, when you’re reviewing the problem, you realize that you picked the wrong answer entirely. Why does this happen, and how can you stop it?

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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.

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

Have you ever worked with someone who inevitably managed to come up with things to do that were a complete waste of time? Maybe it was an insecure boss who was never confident about what he was doing, so he went for the “everything and the kitchen sink” approach to generating deliverables in the last few days before the deadline. Or maybe it was a fellow student on a group project, someone so diligent (cough, cough) that she wanted to turn in a 20-page report when the teacher suggested 10 pages (and actually specified a 12-page limit).

You know who I’m talking about, right? We’ve all run across these situations in our academic or working lives. You want to be polite…but you also want to get your work done and not waste time on activities that don’t really help you reach the overall goal.

The GMAT is trying to waste your time

Okay, the test writers are not literally sitting there cackling and saying, “How can we get them to waste their lives?!?” But the overall sentiment still holds because of the way that the GMAT is constructed. You already know the classic “If you get something right, they give you something harder” pattern, right?

Well, at some point, that “something harder” is going to be something that isn’t worth your time. You’re probably not going to get it right no matter what you do. Even if you do, you’re going to use up valuable time that you could be using on other problems.

Most important of all, you’re going to be using up your finite brain energy on something that probably isn’t going to pay off. How many times in your life have you crashed towards the end of a test or a long day at work because your brain just couldn’t keep going any longer? The GMAT is a “where you end is what you get” test: if you crash before the end of the section, your score will suffer greatly.

This is basically no different than that co-worker who’s trying to get you to build a marketing presentation when the client has specifically requested that you analyze the pros and cons of acquiring a competitor. Tomorrow at the client meeting, it won’t matter how good your intentions were. Your client is going to be mad that you wasted time on something that doesn’t actually help them.

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Memorize what? I’m not going to tell you yet. Try this problem from the GMATPrep® free practice tests first and see whether you can spot the most efficient solution.

All right, have you got an answer? How satisfied are you with your solution? If you did get an answer but you don’t feel as though you found an elegant solution, take some time to review the problem yourself before you keep reading.

Step 1: Glance Read Jot

Take a quick glance; what have you got? PS. A given equation, xy = 1. A seriously ugly-looking equation. Some fairly “nice” numbers in the answers. Hmm, maybe you should work backwards from the answers?

Jot the given info on the scrap paper.

Step 2: Reflect Organize

Oh, wait. Working backwards isn’t going to work—the answers don’t stand for just a simple variable.

Okay, what’s plan B? Does anything else jump out from the question stem?

Hey, those ugly exponents…there is one way in which they’re kind of nice. They’re both one of the three common special products. In general, when you see a special product, try rewriting the problem usually the other form of the special product.

Step 3: Work

Here’s the original expression again:

Let’s see.

Interesting. I like that for two reasons. First of all, a couple of those terms incorporate xy and the question stem told me that xy = 1, so maybe I’m heading in the right direction. Here’s what I’ve got now:

And that takes me to the second reason I like this: the two sets of exponents look awfully similar now, and they gave me a fraction to start. In general, we’re supposed to try to simplify fractions, and we do that by dividing stuff out.

How else can I write this to try to divide the similar stuff out? Wait, I’ve got it:

The numerator: 

The denominator: 

They’re almost identical! Both of the terms cancel out, as do the terms, leaving me with:

I like that a lot better than the crazy thing they started me with. Okay, how do I deal with this last step?

First, be really careful. Fractions + negative exponents = messy. In order to get rid of the negative exponent, take the reciprocal of the base:

Next, dividing by 1/2 is the same as multiplying by 2:

That multiplies to 16, so the correct answer is (D).

Key Takeaways: Special Products

(1) Your math skills have to be solid. If you don’t know how to manipulate exponents or how to simplify fractions, you’re going to get this problem wrong. If you struggle to remember any of the rules, start building and drilling flash cards. If you know the rules but make careless mistakes as you work, start writing down every step and pausing to think about where you’re going before you go there. Don’t just run through everything without thinking!

(2) You need to memorize the special products and you also need to know when and how to use them. The test writers LOVE to use special products to create a seemingly impossible question with a very elegant solution. Whenever you spot any form of a special product, write the problem down using both the original form and the other form. If you’re not sure which one will lead to the answer, try the other form first, the one they didn’t give you; this is more likely to lead to the correct answer (though not always).

(3) You may not see your way to the end after just the first step. That’s okay. Look for clues that indicate that you may be on the right track, such as xy being part of the other form. If you take a few steps and come up with something totally crazy or ridiculously hard, go back to the beginning and try the other path. Often, though, you’ll find the problem simplifying itself as you get several steps in.

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

Some Data Sufficiency questions present you with scenarios: stories that could play out in various complicated ways, depending on the statements. How do you get through these with a minimum of time and fuss?

Try the below problem. (Copyright: me! I was inspired by an OG problem; I’ll tell you which one at the end.)

* “During a week-long sale at a car dealership, the most number of cars sold on  any one day was 12. If at least 2 cars were sold each day, was the average daily number of cars sold during that week more than 6?

“(1) During that week, the second smallest number of cars sold on any one day was 4.

“(2) During that week, the median number of cars sold was 10.”

First, do you see why I described this as a “scenario” problem? All these different days… and some number of cars sold each day… and then they (I!) toss in average and median… and to top it all off, the problem asks for a range (more than 6). Sigh.

Okay, what do we do with this thing?

Because it’s Data Sufficiency, start by establishing the givens. Because it’s a scenario, Draw It Out.

Let’s see. The “highest” day was 12, but it doesn’t say which day of the week that was. So how can you draw this out?

Neither statement provides information about a specific day of the week, either. Rather, they provide information about the least number of sales and the median number of sales.

The use of median is interesting. How do you normally organize numbers when you’re dealing with median?

Bingo! Try organizing the number of sales from smallest to largest. Draw out 7 slots (one for each day) and add the information given in the question stem:

Now, what about that question? It asks not for the average, but whether the average number of daily sales for the week is more than 6. Does that give you any ideas for an approach to take?

Because it’s a yes/no question, you want to try to “prove” both yes and no for each statement. If you can show that a statement will give you both a yes and a no, then you know that statement is not sufficient. Try this out with statement 1

(1) During that week, the least number of cars sold on any one day was 4.

Draw out a version of the scenario that includes statement (1):

Can you find a way to make the average less than 6? Keep the first day at 2 and make the other days as small as possible:

The sum of the numbers is 34. The average is 34 / 7 = a little smaller than 5.

Can you also make the average greater than 6? Try making all the numbers as big as possible:

(Note: if you’re not sure whether the smallest day could be 4—the wording is a little weird—err on the cautious side and make it 3.)

You may be able to eyeball that and tell it will be greater than 6. If not, calculate: the sum is 67, so the average is just under 10.

Statement (1) is not sufficient because the average might be greater than or less than 6. Cross off answers (A) and (D).

Now, move to statement (2):

(2) During that week, the median number of cars sold was 10.

Again, draw out the scenario (using only the second statement this time!).

Can you make the average less than 6? Test the smallest numbers you can. The three lowest days could each be 2. Then, the next three days could each be 10.

The sum is 6 + 30 + 12 = 48. The average is 48 / 7 = just under 7, but bigger than 6. The numbers cannot be made any smaller—you have to have a minimum of 2 a day. Once you hit the median of 10 in the middle slot, you have to have something greater than or equal to the median for the remaining slots to the right.

The smallest possible average is still bigger than 6, so this statement is sufficient to answer the question. The correct answer is (B).

Oh, and the OG question is DS #121 from OG13. If you think you’ve got the concept, test yourself on the OG problem.

Key Takeaway: Draw Out Scenarios

(1) Sometimes, these scenarios are so elaborate that people are paralyzed. Pretend your boss just asked you to figure this out. What would you do? You’d just start drawing out possibilities till you figured it out.

(2) On Yes/No DS questions, try to get a Yes answer and a No answer. As soon as you do that, you can label the statement Not Sufficient and move on.

(3) After a while, you might have to go back to your boss and say, “Sorry, I can’t figure this out.” (Translation: you might have to give up and guess.) There isn’t a fantastic way to guess on this one, though I probably wouldn’t guess (E). The statements don’t look obviously helpful at first glance… which means probably at least one of them is!

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.
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I’ve been speaking with students lately who aren’t entirely sure how to approach Critical Reasoning (CR) questions when a new one first pops up on the screen. In particular, a lot of students do one thing they shouldn’t be doing: they read the argument too soon.

How can someone read the argument too soon?

It may seem kind of strange to say that someone reads the argument too soon. After all, isn’t that the first thing we do on a CR question? Actually, reading the argument is not the first thing we should do. The first thing we should do is read the question stem.

Then, we’re ready to read the argument, right?

Not so fast.

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This week, we have a follow-on article from Chris Ryan, Manhattan GMAT’s Director of Instructor and Product Development. Chris introduced the concept of layering to us in this article on Sentence Correction. Layering is a technique used by a test writer to make a question more difficult. Today, Chris is going to show us how layering works in data sufficiency questions.

Note: I’ve repeated the introduction from the first article below, in case some of you haven’t read that one. If you did read the first one, the first few paragraphs will be review for you.

We all know that the GMAT is a computer adaptive test, and computer adaptive tests give us questions based on the difficulty level that we earn as we take the test. How do the test writers at ACT (the organization that writes the GMAT) determine which questions are harder than others?

First, ACT engages in a process called “normalization,” wherein all freshly written questions are tested by actual test takers to determine what percentage answer the questions correctly (we know these questions as experimental questions). If too many people answer correctly, the question may need to be toughened up. If too few people answer correctly, the question may need to be dumbed down. ACT is looking to assemble a pool of questions that covers a range of difficulty, from cakewalk to mind-bending, and the test takers help them do so.

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