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08 Jun 2015, 16:01
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| FROM Manhattan GMAT Blog: Everything you need to know about the New Official Guides, Part 1 |
 The new Official Guide books are here! Aren’t you excited?!? Okay, I realize that most people probably aren’t as excited as I am. But there are still some interesting and useful things to know about these new books as you get ready to take the GMAT. So let’s talk about it! In this installment, I’ll discuss additions and changes to quant sections for The Official Guide for GMAT® Review 2016, aka the OG or the big book. Keep an eye out for later installments, in which I’ll discuss the verbal section of the big book, as well as the Quantitative Review and Verbal Review books. I’ll also be providing you with a list of the new questions, in case you decide to study from both the 2015 and 2016 editions. If you haven’t already bought your official guide books, then do buy these latest editions—sure you might be able to get a discount on the 2015 editions, but since you have to spend money anyway, you might as well work from the latest and greatest. If you have already bought the older editions and are debating whether to buy the new ones, too, then you’ve got a decision to make. On the one hand, there are a lot of great new questions in the 2016 editions. On the other, the 2015 edition already has a ton of problems; you may not need even more. If it were me, I’d wait until I’d used up the ones in the materials I already have. If I still felt that I needed more beyond that, then I’d consider getting one or more of the new books. What’s new in OG 2016? Approximately 25% of the questions are brand new, and there are some beauties in the mix. As I worked through the problems, I marveled anew at the skill with which the test writers can produce what I call elegant problems. On the quant side, I saw example after example in which the problem can be solved with little to no computation as long as you can decode and understand the fundamental concept underlying the problem—that’s the real test-taking skill! Rich D’Amato, spokesperson for GMAT, confirmed that a decent number of the new questions were produced relatively recently; that is, you’ll be seeing questions that were on the real exam not too long ago. (The older questions are still great study questions, too; the GMAT is a standardized test so, by definition, the test makers can’t change things too drastically or rapidly. There can be some mild trends over time, though. For example, the test makers may decide that certain idioms should be retired from or introduced for Sentence Correction problems.) The opening chapters of the book describe how the GMAT works and how to study for the test; these sections have not changed. Nor has the Math Review (chapter 4). This is no surprise—again, the GMAT is a standardized test and, as such, it remains very consistent over time. The Diagnostic test in chapter 3 also has not changed. What’s new in Quant? Overall, I noticed multiple new problems that crossed two or (occasionally) even three content areas. For instance, #18 is a geometry question that also crosses into percents, as does overlapping sets Problem #91. I chose those two examples on purpose so that I could also point this out: fractions and percents, in particular, are really good concepts to cross over into any other content area, so make sure you have a very solid foundation in both fractions and percents. I also noticed a few visual questions—a couple of 3-D geometry and some coordinate plane problems that were made much harder by my general tendency to struggle with this kind of visual stuff. If you’re like me, beware; you may decide ahead of time that you want to bail immediately on 3-D or other problems that have a heavy visual component. Problem Solving Of the 230 questions in the Problem Solving (PS) section, 58 of them are new. (Disclaimer: I hope I counted correctly for all of these sections, but I’ve been going through about 1,500 questions and hundreds of pages quickly in order to get this review out to you right away. So please forgive me if I miscounted anything! I’ll correct any errors as soon as I find out about them.) I noticed a number of what I’ll call “practical” questions: the question, usually a story problem, reads like something you might be asked to figure out in the real world. Problem #11, for example, asks you to figure out the minimum number of questionnaires you’d need to mail in order to achieve a certain desired number of responses. (The problem includes an assumed response rate.) Note: I can’t actually reproduce the text of the question for copyright reasons, but I’m citing the problem number so that you can look it up if you do decide to buy the book. Problem #39 can literally be counted out on your fingers—as long as you understand what you’re being asked to do. Be careful with definitions! I also saw several problems that seriously disguised what the question was getting at. I don’t want to spoil you for the questions—better if you can figure it out for yourself!—but take a close look at #68 and #83. On the surface, these would be classified as algebra. But at least one can be done more easily using a different set of concepts. (I’ll tell you at the end of this article. But don’t look until you’ve tried to figure it out yourself!) I used smart numbers to solve a number of the problems and I also worked backwards multiple times. In other words, these strategies are just as important as they always were. I did notice one question (#99) on which we could use smart numbers but the form of the answers indicated that it’d almost certainly be easier to do algebra. Look at the problem; you’ll see what I mean! Finally, let’s talk about those elegant questions. If you can understand the concepts underlying #97, then you barely need to calculate anything at all—even though it looks as though you’re going to need to do some annoying algebra to answer the problem. Likewise, #107 has a huge disguise that, once uncovered, allows you to answer in two seconds without calculating anything at all. (Again, I’ll tell you what this is at the end of this article.) Data Sufficiency Of the 174 Data Sufficiency (DS) problems, 45 are new to this edition of the OG. Continuing on the theme from PS, I was really struck by the number of new story problems for which translation is the whole key. If you translate carefully and accurately, then you don’t need to do anything more to solve. For example, #38 looks particularly nasty. Translate that thing very carefully, though, and you won’t have to do any messy calculations to answer. Problem #83 is another example; the story is pretty confusing, but if you can lay out the parts carefully and clearly, then the rest of the problem is more about logic than math. Next, I used testing cases numerous times; as with PS, the standard test-taking strategies are still in full evidence on DS. I also noticed that, as before, it’s crucial to make sure you know what you were asked to find. This is true on PS too, of course, but DS tends to set more traps around solving for the wrong thing. Check out #39. You can’t find t by itself, but you can find t2, and that’s good enough to solve. So what were all those cool disguises and tricks you mentioned? Here you go. Again, do not read this until you have worked on these problems yourself! If you can figure out what’s going on yourself, the lesson will stick much better in the end. J PS #68 and #83. These two problems share a consecutive integer disguise. The givens can be read to mean consecutive integers (the second one has to be rearranged to do so) and, since in each case the two terms multiply to an integer, that tells you that you’re dealing with the factors of that integer. For instance, in #68, the factors of 24 are (1, 24), (2, 12), (3, 8), and (4, 6). BUT note that the problem does not actually mention factors or specify positive numbers, so you also have to take into account that the pairs could be negative. Next, you know that they have to be consecutive odds or consecutive evens, so the only two pairs that work are (4, 6) and (-4, -6). From there, you can figure out the answer. Problem #83 has a similar disguise, although it can also be solved via quadratic equations. PS #97. The question asks you to maximize the depth, N(t). The -20(t – 5)2 term has that negative sign out front, so it could reduce the depth, so you need to minimize the negative value. How? Make the (t – 5) term equal to zero! PS #107. I love this one. It’s a weighted average question in disguise. The formula x + y = 1 signifies that the two weightings add up to 100%: x + y = 100%, where x and y are the two weightings. The formula 100x + 200y signifies the weightings that you’re applying to each of the two endpoints, 100 and 200. The weighted average must be somewhere between the two starting numbers / endpoints, so only two of the roman numerals can work. DS #38. The question tells you to set (1/12 + kv2) equal to 5/12. Then it asks you for v. If you know k, then you can find v. So the real question is whether the statement allows you to find k. Statement (1) obviously does, and statement (2) also does, because it gives you another equation: (1/12) + k(30)2 = 1/6. DS #83. There are x processors. Each processor can process up to y calls. Think about what this means—maybe even draw a picture. Note that x has to be at least 1 and y has to be at least 1. If you have x = 1 processor that can process y = 500 calls, then sure, you can process 500 calls at once. If you have x = 10 processors that can process y = 10 calls each, then nope, you can’t process 500 calls at once. So you need to know something about x and y in order to answer. It looks, then, like statements (1) and (2) can’t work alone, since each talks about only one variable. But don’t forget the constraint that each has to be at least 1!! If you have x = 600 processors, then you can definitely process 500 calls, since each processor has to be able to process at least one call. What about Verbal? And the other books? Next time, we’ll dive into the verbal sections of the Big OG. Then, we’ll discuss the quant and verbal supplements, and finally, I’ll provide you with lists of the new questions in each book and also the new question numbers for the old questions that remain in the book from the last edition. Happy studying! The post Everything you need to know about the New Official Guides, Part 1 appeared first on GMAT. |
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12 Jun 2015, 19:00
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| FROM Manhattan GMAT Blog: Everything you need to know about the New Official Guides, Part 2 |
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The new Official Guide books are here! Last time, we talked about the Quant portion of The Official Guide for GMAT, aka the OG or the big book. In this installment, we’ll discuss the Verbal section of the big book. Later installments will talk about the Quant Review and Verbal Review (the smaller books), as well as question lists for the new questions. (Note: I have not yet had time to analyze the IR problems that come via your special online access. I’ll get to that soon—the quant and the verbal are higher priority!) Part 1 included an overview of the changes to the whole book; I’ve included that overview here as well (the next section!), in case you’re reading this installment first. (The only difference is one sentence in the first paragraph.) What’s new in OG 2016? Approximately 25% of the questions are brand new, and there are some beauties in the mix. As I worked through the problems, I marveled anew at the skill with which the test writers can produce what I call elegant problems. On the verbal side, I loved how some of the new questions wove meaning into the issue of Sentence Correction; if you have been focusing on grammar and shortchanging meaning, you’re definitely going to need to change your approach. Rich D’Amato, spokesperson for GMAT, confirmed that a decent number of the new questions were produced relatively recently; that is, you’ll be seeing questions that were on the real exam not too long ago. (The older questions are still great study questions, too; the GMAT is a standardized test so, by definition, the test makers can’t change things too drastically or rapidly. There can be some mild trends over time, though. For example, the test makers may decide that certain idioms should be retired from or introduced for Sentence Correction problems.) The opening chapters of the book describe how the GMAT works and how to study for the test; these sections have not changed. Nor has the Math Review (chapter 4). This is no surprise—again, the GMAT is a standardized test and, as such, it remains very consistent over time. The Diagnostic test in chapter 3 also has not changed. What’s new in SC? Of the 140 questions in the Sentence Correction (SC) chapter, 35 are new. Sentence Correction is always difficult to classify because one question can test multiple different topics, and one difference can straddle the line between two topics. A full 16 of the new questions, though, test meaning or sentence structure (or both). I thought that there were some interesting sentence structure examples; keep an eye out for my eventual problem lists, in which I’ll add notes about things that caught my eye when doing the problems. When comparing the questions that were dropped to the ones that were added, meaning definitely jumped in the count. This is again a judgment call: when do we classify something as pure meaning vs. a grammar error that messes up meaning? But using a consistent standard across all of the questions, I counted 10 new meaning SCs compared to 3 dropped. All of the other categories didn’t change substantially (not a big surprise, since this is a standardized test). I do want to point out that 19 out of the 35 new questions cover parallelism or comparisons. In other words, these two topics were important before and they still are. Study them! What’s new in CR? Of the 130 questions in the Critical Reasoning (CR) chapter, 35 are new. When comparing the number of questions dropped vs. added, it was the case that Strengthen questions jumped a bit, while Weaken and Inference dropped a bit. These trends also appeared in the Verbal supplement, so I’m noting them here, though I also want to add that the numbers are small enough that we can’t say definitively that they reflect any kind of change in the test. (Also, there were some other seeming trends that didn’t actually hold for both books, so I’m ignoring those.) All of the questions except for one (#39) fit neatly into our existing classification categories. I’m still trying to decide how I would classify #39. It’s in the Assumption Family but I keep going back and forth on whether I would call it a Strengthen or a Weaken. The question stem alone is most like a weaken (an “alternative explanation” would be like saying “Hey, here’s a better conclusion than the one you came up with!”). But the reasoning for the correct answer choice can be interpreted as a Strengthen. I’m going to be asking some fellow teachers, and even GMAC, about this one; I’ll get back to you. What’s new in RC? We lost 3 shorter and 3 longer passages from the 2015 edition; 3 of these were social science, 2 were science, and 1 was business. We gained 4 longer passages and 2 shorter ones; 4 of these were science and 2 were social science. I’m not sure whether that indicates any kind of increased emphasis on science topics, but it’s certainly interesting that not one of the new passages is a business passage. There are 31 new questions total out of 139 questions total. 15 specific detail question were dropped and only 7 were added. That 8-question differential was added to specific purpose (why) questions (+5), weaken (+2), and main idea (+1). The latter two are pretty small changes, but I found it very interesting that 5 why questions were added. What else? Tell me more! I’ve got more for you! In later installments, we’ll talk about the Quant Review and Verbal Review (the smaller OGs) and I’ll give you lists of the new question numbers as well as the updated question numbers for the problems that are in both books. Until then, happy studying! The post Everything you need to know about the New Official Guides, Part 2 appeared first on GMAT. |
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17 Jun 2015, 17:00
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| FROM Manhattan GMAT Blog: Everything you need to know about the New Official Guides, Part 3 |
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I have now done every last one of the new quant problems in both new books—and there are some really neat ones! I’ve also got some interesting observations for you. (If you haven’t yet read my earlier installments, start here.) In this installment, I’ll discuss my overall conclusions for quant and I’ll also give you all of the problem numbers for the new problems in both the big OG and the smaller quant-only OG. What’s new in Quant? Now that I’ve seen everything, I’ve been able to spot some trends across all of the added and dropped questions. For example, across both The Official Guide for GMAT® Review (aka the big book) and The Official Guide for GMAT® Quant Review (aka quant-only or the quant supplement), Linear Equation problems dropped by a count of 13. This is the differential: new questions minus dropped questions. That’s a pretty big number; the next closest categories, Inequalities and Rates & Work, dropped by 5 questions each. I’m not convinced that a drop of 5 is at all significant, but I decided that was a safe place to stop the “Hmm, that’s interesting!” count. Now, a caveat: there are sometimes judgment calls to make in classifying problems. Certain problems cross multiple content areas, so we do our best to pick the topic area that is most essential in solving that problem. But that 13 still stands out.  The biggest jump came from Formulas, with 10 added questions across both sources. This category includes sequences and functions; just straight translation or linear equations would go into those respective categories, not formulas. Positive & Negative questions jumped by 7, weighted average jumped by 6, and coordinate plane jumped by 5. Given that Linear Equations dropped and Formulas jumped, could it be the case that they are going after somewhat more complex algebra now? That’s certainly possible. I didn’t feel as though the new formula questions were super hard though. It felt more as though they were testing whether you could follow directions. If I give you a weird formula with specific definitions and instructions, can you interpret correctly and manipulate accordingly? If you think about it, work is a lot more like this than “Oh, here are two linear equations; can you solve for x?” So it makes sense that they would want to emphasize questions of a more practical nature. Anything interesting about the new questions? In an earlier installment, I told you about some interesting problems from the big book. Here are a few more observations from the Quant-only supplemental book. Problem Solving Of the 176 questions in the Problem Solving (PS) section, 44 of them are new. (Disclaimer: I hope I counted correctly for all of these sections, but I’ve been going through about 1,500 questions and hundreds of pages quickly in order to get this review out to you right away. So please forgive me if I miscounted anything! I’ll correct any errors as soon as I find out about them.) Note: I can’t actually reproduce the text of the question for copyright reasons, but I’ll cite the problem number so that you can look it up if you do decide to buy the book. A number of questions relied on some type of pattern recognition: #125, #143, #161. They’re not interested in you doing crazy math. They’re interested in whether you can recognize patterns and draw some kind of meaningful conclusion. In my notes, I labeled #80 “Wow. That’s just mean.” And #152 got a “Pure evil” tag. (#152 requires mental manipulation of a 3-D shape and that’s just not something I have ever been able to do.) I’d far rather work backwards on #127 than do the actual math. Others may feel differently, but the textbook math on this one is pretty annoying. Data Sufficiency Of the 124 Data Sufficiency (DS) problems, 32 are new to this edition of the Quant OG. There were some doozies. I couldn’t believe #124, the highest numbered question in the section: a parabola inequality (not even an equation!). Now, if you like geometry, great—learn how to tackle parabolas. If you don’t, then if you happen to get one of these on the real test, give yourself a mental high five for earning this question, then pick your favorite letter and move on! I almost fell into the trap on #123. I’m so used to rate and work questions specifying that whatever was moving at a steady rate that I almost didn’t notice the omission in this one… Also, as with the big book, I was testing cases all the time on these DS problems. That technique is just a lifesaver (and it even works on some PS problems!). So what are all the NEW problem numbers? Here you go! I’ve got these organized by book and question type. The Official Guide for GMAT® Review 2016 (aka the big OG) Problem Solving Key: FDP = Fractions, Decimals, & Percents; WP = Word Problems; NP = Number Properties   Data Sufficiency Key: FDP = Fractions, Decimals, & Percents; WP = Word Problems; NP = Number Properties   The Official Guide for GMAT® Quant Review 2016 (aka the quant-only book) Problem Solving Key: FDP = Fractions, Decimals, & Percents; WP = Word Problems; NP = Number Properties   Data Sufficiency Key: FDP = Fractions, Decimals, & Percents; WP = Word Problems; NP = Number Properties   What about Verbal? Next time, we’ll dive into the final summary of everything verbal and I’ll also have the problem lists for you. Until then, happy studying! The post Everything you need to know about the New Official Guides, Part 3 appeared first on GMAT. |
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