The post Tackling GMAT Critical Reasoning Boldface Questions appeared first on Veritas Prep Blog.

]]>We have often found that one strategy, which is very helpful in other question types too, helps sort out most questions of this type, though not in the same way. That strategy is – ‘find the conclusion(s)’

The conclusion of the argument is the position taken by the author.

Boldface questions (and others too) sometimes have more than one conclusion – One would be the conclusion of the argument i.e. the author’s conclusion. The argument could mention another conclusion which could be the conclusion of a certain segment of people/ some scientists/ some researchers/ a politician etc. We need to segregate these two and how each premise supports/opposes the various conclusion. Once this structure is in place, we automatically find the answer. Let’s see how with an example.

**Question:**** Recently, motorists have begun purchasing more and more fuel-efficient economy and hybrid cars that consume fewer gallons of gasoline per mile traveled. There has been debate as to whether we can conclude that these purchases will actually lead to an overall reduction in the total consumption of gasoline across all motorists.** The answer is no, since motorists with more fuel-efficient vehicles are likely to drive more total miles than they did before switching to a more fuel-efficient car, negating the gains from higher fuel-efficiency.

Which of the following best describes the roles of the portions in bold?

(A)The first describes a premise that is accepted as true; the second introduces a conclusion that is opposed by the argument as a whole.

(B)The first states a position taken by the argument; the second introduces a conclusion that is refuted by additional evidence.

(C)The first is evidence that has been used to support a position that the argument as a whole opposes; the second provides information to undermine the force of that evidence.

(D)The first is a conclusion that is later shown to be false; the second is the evidence by which that conclusion is proven false.

(E)The first is a premise that is later shown to be false; the second is a conclusion that is later shown to be false.

**Solution**: As our first step, let’s try to figure out the conclusion of the argument:

The author’s view is that “purchases of fuel efficient vehicles will NOT lead to an overall reduction in the total consumption of gasoline across all motorists.”

This is the position the argument (and author) takes.

The argument gives us another conclusion: these purchases will actually lead to an overall reduction in the total consumption of gasoline across all motorists.

Some people take this position (implied by the use of “there has been debate”)

This is our second bold statement. It introduces the opposing conclusion.

Let’s look at our options now.

(A) The first describes a premise that is accepted as true; the second introduces a conclusion that is opposed by the argument as a whole.

The first bold statement: Recently, motorists have begun purchasing more and more fuel-efficient economy and hybrid cars that consume fewer gallons of gasoline per mile traveled.

This is a premise and has been accepted as true. We know it has been accepted as true since the last line ends with – “…negating the gains from higher fuel-efficiency”

We have seen above that the second bold statement tells us about a conclusion that the argument opposes.

So (A) is correct. We have found our answer but let’s look at the other options too.

(B) The first states a position taken by the argument; the second introduces a conclusion that is refuted by additional evidence.

The first bold statement is a premise. It is not the position taken by the argument. Let’s move on.

(C) The first is evidence that has been used to support a position that the argument as a whole opposes; the second provides information to undermine the force of that evidence.

This option often confuses test-takers.

The evidence is – “Recently, motorists have begun purchasing more and more fuel-efficient economy and hybrid cars that consume fewer gallons of gasoline per mile traveled.”

That is, “the motorists have begun purchasing fuel efficient cars that give better mileage.”

The second bold statement does not undermine this evidence at all. In fact, it builds up on it with – “This brings up a debate on whether it will lead to overall decreased fuel consumption?”

Hence (C) is not correct.

(D)The first is a conclusion that is later shown to be false; the second is the evidence by which that conclusion is proven false.

The first bold statement is not a conclusion. So no point dwelling on this option.

(E)The first is a premise that is later shown to be false; the second is a conclusion that is later shown to be false.

The premise is taken to be true. The argument ends with “… the gains from higher fuel-efficiency”. Hence, this option doesn’t stand a chance either.

We hope you see how easy it is to break down the options once we identify the conclusion(s).

Keep practicing!

*Getting ready to take the GMAT? We have free online GMAT seminars running all the time. And, be sure to follow us on Facebook, YouTube, Google+, and Twitter!*

*Karishma, a Computer Engineer with a keen interest in alternative Mathematical approaches, has mentored students in the continents of Asia, Europe and North America. She teaches the **GMAT** for Veritas Prep and regularly participates in content development projects such as this blog!*

The post Tackling GMAT Critical Reasoning Boldface Questions appeared first on Veritas Prep Blog.

]]>The post GMAT Tip of the Week Is Not A Player, It Just Crushes A Lot appeared first on Veritas Prep Blog.

]]>On a test-taker’s route to a strong section score, there lie a handful of questions that tempt you to devote several fruitless minutes playing around with equations, calculations, and techniques that aren’t working. A few questions later you look at the clock and realize that even though 90% of the problems have gone well for you, you’re several minutes off your target pace…all because of that one big punisher, the question you should have left alone.

Fortunately, Big Punisher has a mantra for you to keep in mind on test day:

“I’m not a player, I just crush a lot”

Meaning, of course, that you’re not the kind of test-taker who aimlessly plays around with the 3-4 “big punisher” questions that will ruin the time you have left for the others. You quickly identify that no one question is worth taking your whole pacing strategy on (as Snoop would say, “I’m too swift on my toes to get caught up with you hos,” hos, of course, being short for “horribly involved problems that I’ll probably get wrong anyway) and bank that time for the many other problems that you’ll crush…a lot.

Functionally that means this: when you realize that you’re more likely wasting time than progressing toward a right answer, cut your losses and move on so that you save the time for the problems that you will undoubtedly get right…as long as you have a reasonable amount of time for them. You might consider paying homage to Big Pun by using his name as a quick mnemonic for your strategic options:

**P**: Pick Numbers. If the calculations or algebra you’re performing seems to either be going in circles or getting worse, look back and see if you could simply pick numbers instead. This often works when you’re dealing with variables as parts of the answer choices.

**U**: Use Answer Choices. Again, if you feel like you’re running in circles, check and see if there are clues in the answer choices or if you can plug them in and backsolve directly.

**N**: Not Worth My Time. And if a quick assessment tells you that you can’t pick numbers or use answer choices, recognize that this problem simply isn’t worth your time, and blow in a guess. Remember: you’re not a player – you won’t let the test bait you into playing with a single crazy question for more than a minute without a direct path to the finish line – so save the time to focus on crushing a lot of problems that you know you can crush.

On your journey to completing entire GMAT sections on time, heed Big Pun’s warning: don’t stop (to play around with questions you already know you’re not getting right), get it, get it – meaning pick up the pace to have meaningful time to spend on the questions you can get. The biggest punisher of what should be high GMAT scores is poor time management, almost always caused by spending far too long on just a few problems. So remember: you’re not a player on those problems…go out there and crush a lot of the problems you know you can crush.

*Getting ready to take the GMAT? We have free online GMAT seminars running all the time. And as always, be sure to follow us on Facebook, YouTube, Google+ and Twitter!*

*By Brian Galvin.*

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]]>The post GMAT Tip of the Week: The Song Remains the Same appeared first on Veritas Prep Blog.

]]>Biggie’s “Hypnotize” samples directly from “La Di Da Di” (originally by Doug E. Fresh – yep, he’s the one who inspired “The Dougie” that Cali Swag District wants to teach you – and Slick Rick). “Biggie Biggie Biggie, can’t you see, sometimes your words just hypnotize me…” was originally “Ricky, Ricky, Ricky…” And right around the same time, Snoop Dogg and 2Pac just redid the entire song just about verbatim, save for a few brand names.

The “East Coast edit” of Chris Brown’s “Loyal”? French Montana starts his verse straight quoting Jay-Z’s “I Just Wanna Love U” (“I’m a pimp by blood, not relation, I don’t chase ’em, I replace ’em…”), which (probably) borrowed the line “I don’t chase ’em I replace ’em” from a Biggie track, which probably got it from something else. And these are just songs we heard on the radio this morning driving to work…

The point? Hip hop is a constant variation on the same themes, one of the greatest recycling centers the world has ever known.

And so is the GMAT.

Good test-takers – like veteran hip hop heads – train themselves to see the familiar within what looks (or sounds) unique. A hip hop fan often says, “Wait, where I have heard that before?” and similarly, a good test-taker sees a unique, challenging problem and says, “Wait, where have I seen that before?”

And just like you might recite a lyric back and forth in your mind trying to determine where you’ve heard it before, on test day you should recite the operative parts of the problem or the rule to jog your memory and to remind yourself that you’ve seen this concept before.

Is it a remainder problem? Flip through the concepts that you’ve seen during your GMAT prep about working with remainders (“the remainder divided by the divisor gives you the decimals; when the numerator is smaller then the denominator the whole numerator is the remainder…”).

Is it a geometry problem? Think of the rules and relationships that showed up on tricky geometry problems you have studied (“I can always draw a diagonal of a rectangle and create a right triangle; I can calculate arc length from an inscribed angle on a circle by doubling the measure of that angle and treating it like a central angle…”).

Is it a problem that asks for a seemingly-incalculable number? Run through the strategies you’ve used to perform estimates or determine strange number properties on similar practice problems in the past.

The GMAT is a lot like hip hop – just when you think they’ve created something incredibly unique and innovative, you dig back into your memory bank (or click to a jazz or funk station) and realize that they’ve basically re-released the same thing a few times a decade, just under a slightly different name or with a slightly different rhythm.

The lesson?

You won’t see anything truly unique on the GMAT. So when you find yourself stumped, act like the old guy at work when you tell him to listen to a new hip hop song: “Oh I’ve heard this before…and actually when I heard it before in the ’90s, my neighbor told me that she had heard it before in the ’80s…” As you study, train yourself to see the similarities in seemingly-unique problems and see though the GMAT’s rampant plagiarism of itself.

The repetitive nature of the GMAT and of hip hop will likely mean that you’re no longer so impressed by Tyga, but you can use that recognition to be much more impressive to Fuqua.

*Getting ready to take the GMAT? We have free online GMAT seminars running all the time. And as always, be sure to follow us on Facebook, YouTube, Google+ and Twitter!*

*By Brian Galvin.*

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]]>The post 3.14 Reasons to Love Pi appeared first on Veritas Prep Blog.

]]>As you study for a major standardized test, you know that you’ll be working with circles at some point, so here are 3.14 reasons that you should learn to love the number π:

**1) Pi should make you salivate.**

On any standardized test question, if you see the value π, whether in the question itself of in the answer choices, that π tells you that you’re dealing with a circle. Some test questions disguise what they want you to do – you may have to draw in a triangle to find the diagonal of a square, for example – but circle problems cannot hide from you! π is a dead giveaway that you’re dealing with a circle, so like Pavlov’s Dog, when you see that signal, π, you should respond with a biological response and conjure up all your knowledge of circles immediately.

**2) Pi can be easily cut into slices.**

Whether you’re dealing with a section of the area of a circle or a section of the circumference (arc length), the fact that a circle is perfectly symmetrical makes the job of cutting that circle into slices an easy one. With arc length, all you end up doing is using the central angle to determine the proportion of that section (angle/360 = proportion of what you want), making it very easy to slice up a circle using π. With the area of a section, as long as the arms of that section are equal to the radius of the circle, you can do the exact same thing. Just like an apple pie or **pi**zza pie, if you’re cutting into slices from the center of the circle, cutting that pie into slices is a relatively simple task.

**3) You can take your pi to go.**

You will almost never have to calculate the value of pi on a standardized test: almost always, the symbol π will appear in the answer choices (e.g. 5π, 7π, etc.), meaning that you can just carry π through your calculations and bring it with you to the answer choices. If, for example, you need to calculate the area of a circle with radius 3, you’ll plug the radius into your formula [π(3^2)] and just end up with 9π, which you’ll find in the answer choices. With most other symbols (x, y, r, etc.) you’ll need to do some work to turn them into numbers. Pi is great because you can take it to go.

**3.14) The decimals in pi are just a sliver.**

If you ever are asked to “calculate” pi (which typically means that the question is asking you to approximate a value, not to directly calculate it), you can use the fact that the .14 in 3.14 is a tiny sliver of a decimal. For example, if you had to estimate a value for 5π, 5 times 3 is clearly 15, but 5 times .14 is so small that it won’t require you to go all the way to 16. So if your answer choices were 15.7, 16.1, 16.4, etc., you could rely on the fact that the decimal .14 is so small that you can eliminate all the 16s.

Other irrational numbers like the square root of 2 and square root of 3 have decimal places more in the neighborhood of .5, so you will probably need to work a little harder to estimate how they’ll react when you multiply them even by relatively small numbers. But π’s decimals come in small slivers, allowing you to manage your calculations in bite size **pi**eces.

So remember – there are 3.14 (and counting) reasons to love pi, and learning to love pi can help turn your test day into a **pi**ece of cake.

*Are you getting ready to take the SAT, ACT, GMAT or GRE? Check out our website for a variety of helpful test prep resources. And as always, be sure to follow us on Facebook, YouTube, Google+ and Twitter!*

*By Brian Galvin.*

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]]>The post Quarter Wit, Quarter Wisdom: Beware of Assumption in GMAT Critical Reasoning Options appeared first on Veritas Prep Blog.

]]>*In 2009, a private school spent $200,000 on a building which housed classrooms, offices, and a library. In 2010, the school was unable to turn a profit. Therefore, the principal should be fired.*

*Each of the following, if true, weakens the author’s conclusion EXCEPT:*

*(A) The principal was hired primarily for her unique ability to establish a strong sense of community, which many parents cited as a quality that kept children enrolled in the school longer.*

*(B) The new library also features a seating area big enough for all students to participate in cultural arts performances, which the head of school intends to schedule more frequently now.*

*(C) The principal was hired when the construction of the new building was almost completed.*

*(D) A significant number of families left the school in 2010 because a favourite teacher retired.*

*(E) More than half of the new families who joined the school in 2010 cited the beautiful new school facility as an important factor in their selection of the school.*

This is a weaken/exception question, so four of the five answer choices will weaken the argument, while the fifth option (which will be the correct answer) will either not have any impact on the argument or it might even strengthen it. As we know, such questions require a bit more effort to answer, since four of the five options will definitely be relevant to the argument. The important thing is to focus on what we are given and not assume what the various answer options may or may not lead to. Let’s understand this:

The gist of the argument:

- Last year, a lot of money was spent to construct a new building with many amenities.
- This year, the school did not see a profit.
- Hence, fire the principal.

Based on the two given facts – “a lot of money was spent to make the building in 2009” and “the school did not see a profit in 2010” – the author has decided to fire the principal. Many pieces of information could weaken his stance. For example:

- It was not the principal’s decision to construct the building.
- The school’s revenue in 2010 took a hit because of some other factor.
- The school’s losses reduced by a huge amount in 2010 and the probability of it seeing a profit in 2011 is high.

Information such as this could improve the principal’s case to stay. We know that for this particular question, there will only be one option that does not help the principal.

You will have to choose the answer choice which, with the given information, does not help the principal’s case. Let’s look at the options now:

*(A) The principal was hired primarily for her unique ability to establish a strong sense of community, which many parents cited as a quality that kept children enrolled in the school longer.*

With this answer choice, we see that the principal was hired not to increase school profits, but for another critical purpose. Perhaps the school’s finance department is in charge of worrying about profits, and so the head of that department needs to be fired! This answer choice makes a strong case for keeping the principal, and hence, weakens the author’s argument.

*(B) The new library also features a seating area big enough for all students to participate in cultural arts performances, which the head of school intends to schedule more frequently now.*

If true, this statement would have no impact on whether or not the principal should be fired. It describes an amenity provided by the new building and how it will be used – it neither strengthens nor weakens the principal’s case to stay, hence, this is the correct answer choice. But let’s look at the rest of the options too, just to be safe:

*(C) The principal was hired when the construction of the new building was almost completed.*

This tells us that the new building was not her decision. So if it did not have the desired effect, she cannot be blamed for it. So it again helps her case.

(D) A significant number of families left the school in 2010 because a favourite teacher retired.

This answer choice shows that there was another reason behind the school’s loss in profit. The construction of the building could still be a good idea that leads to future profits, which the principal’s case and weakens the author’s argument.

*(E) More than half of the new families who joined the school in 2010 cited the beautiful new school facility as an important factor in their selection of the school.*

For some reason, this is the answer choice that often trips up students. They feel that it doesn’t help the principal’s case – that because the new building attracts students, if there are losses, it means that the loss is due to a fault with the new building, and thus, the principal is at fault. But note that we are assuming a lot to arrive at that conclusion. All we are told is that the new building is attracting students. This means the new building is serving its purpose – it is generating extra revenue. The fact that the school is still experiencing losses could be explained by many different reasons.

Since the author’s decision to fire the principal is based solely on the premise that a lot of money was spent to construct the new building, which now seems to serve no purpose (because the school experienced losses), this answer choice certainly weakens the argument. The option tells us that the principal’s decision to make the building was justified, so it helps her case to stay with the school.

After examining each answer choice, we can see that the answer is clearly B. Remember, in Critical Reasoning questions it is crucial to come to conclusions only based on the facts that are given – creating assumptions based on information that is not given can lead you to fall in a Testmaker trap.

*Getting ready to take the GMAT? We have free online GMAT seminars running all the time. And, be sure to follow us on Facebook, YouTube, Google+, and Twitter!*

*Karishma, a Computer Engineer with a keen interest in alternative Mathematical approaches, has mentored students in the continents of Asia, Europe and North America. She teaches the **GMAT** for Veritas Prep and regularly participates in content development projects such as this blog!*

The post Quarter Wit, Quarter Wisdom: Beware of Assumption in GMAT Critical Reasoning Options appeared first on Veritas Prep Blog.

]]>The post GMAT Tip of the Week: Big Sean Says Your GMAT Score Will Bounce Back appeared first on Veritas Prep Blog.

]]>If you have a car stereo or Pandora account, you’ve undoubtedly heard Big Sean talking about bouncing back this month. “Bounce Back” is a great anthem for anyone hitting a rough patch – at work, in a relationship, after a rough day for your brackets during next week’s NCAA tournament – but this isn’t a self-help, “it’s always darkest before dawn,” feel-good article. Big Sean has some direct insight into the GMAT scoring algorithm with Bounce Back, and if you pay attention, you can leverage Bounce Back (off the album “I Decided” – that’ll be important, too) to game-plan your test day strategy and increase your score.

So, what’s Big Sean’s big insight?

The GMAT scoring (and question delivery) algorithm is designed specifically so that you can “take an L” and bounce back. And if you understand that, you can budget your time and focus appropriately. The test is designed so that just about everybody misses multiple questions – the adaptive system serves you problems that should test your upper threshold of ability, and can also test your lower limit if you’re not careful.

What does that mean? Say you, as Big Sean would say, “take an L” (or a loss) on a question. That’s perfectly fine…everyone does it. The next question should be a bit easier, providing you with a chance to bounce back. The delivery system is designed to use the test’s current estimate of your ability to deliver you questions that will help it refine that estimate, meaning that it’s serving you questions that lie in a difficulty range within a few percentile points of where it thinks you’re scoring.

If you “take an L” on a problem that’s even a bit below your true ability, missing a question or two there is fine as long as it’s an outlier. No one question is a perfect predictor of ability, so any single missed question isn’t that big of a deal…if you bounce back and get another few questions right in and around that range, the system will continue to test your upper threshold of ability and give you chances to prove that the outlier was a fluke.

The problem comes when you don’t bounce back. This doesn’t mean that you have to get the next question right, but it does mean that you can’t afford big rough patches – a run of 3 out of 4 wrong or 4 out of 5 wrong, for example. At that point, the system’s estimate of you has to change (your occasional miss isn’t an outlier anymore) and while you can still bounce back, you now run the risk of running out of problems to prove yourself. As the test serves you questions closer to its new estimate of you, you’re not using the problems to “prove how good you are,” but instead having to spend a few problems proving you’re “not that bad, I promise!”

So, okay. Great advice – “don’t get a lot of problems wrong.” Where’s the real insight? It can be found in the lyrics to “Bounce Back”:

*Everything I do is righteous
Betting on me is the right risk
Even in a ***** crisis…*

During the test you have to manage your time and effort wisely, and that means looking at hard questions and determining whether betting on that question is the right risk. You **will** get questions wrong, but you also control how much you let any one question affect your ability to answer the others correctly. A single question can hurt your chances at the others if you:

- Spend too much time on a problem that you weren’t going to get right, anyway
- Let a problem get in your head and distract you from giving the next one your full attention and confidence

Most test-takers would be comfortable on section pacing if they had something like 3-5 fewer questions to answer, but when they’re faced with the full 37 Quant and 41 Verbal problems they feel the need to rush, and rushing leads to silly mistakes (or just blindly guessing on the last few problems). And when those silly mistakes pile up and become closer to the norm than to the outlier, that’s when your score is in trouble.

You can avoid that spiral by determining when a question is not the right risk! If you recognize in 30-40 seconds (or less) that you’re probably going to take an L, then take that L quickly (put in a guess and move on) and bank the time so that you can guarantee you’ll bounce back. You know you’re taking at least 5 Ls on each section (for most test-takers, even in the 700s that number is probably closer to 10) so let yourself be comfortable with choosing to take 3-4 Ls consciously, and strategically bank the time to ensure that you can thoroughly get right the problems that you know you should get right.

Guessing on the GMAT doesn’t have to be a panic move – when you know that the name of the game is giving yourself the time and patience to bounce back, a guess can summon Big Sean’s album title, “I Decided,” as opposed to “I screwed up.” (And if you need proof that even statistics PhDs who wrote the GMAT scoring algorithm need some coaching with regard to taking the L and bouncing back, watch the last ~90 seconds of this video.)

So, what action items can you take to maximize your opportunity to bounce back?

**Right now:** pay attention to the concepts, question types, and common problem setups that you tend to waste time on and get wrong. Have a plan in mind for test day that “if it’s *this* type of problem and I don’t see a path to the finish line quickly, I’m better off taking the L and making sure I bounce back on the next one.”

Also, as you review those types of problems in your homework and practice tests, look for techniques you can use to guess intelligently. For many, combinatorics with restrictions is one of those categories for which they often cannot see a path to a correct answer. Those problems are easy to guess on, however! Often you can eliminate a choice or two by looking at the number of possibilities that would exist without the restriction (e.g. if Remy and Nicki would just patch up their beef and stand next to each other, there would be 120 ways to arrange the photo, but since they won’t the number has to be less than 120…). And you can also use that total to ask yourself, “Does the restriction take away a lot of possibilities or just a few?” and get a better estimate of the remaining choices.

**On test day:** Give yourself 3-4 “I Decided” guesses and don’t feel bad about them. If your experience tells you that betting your time and energy on a question is not the right risk, take the L and use the extra time to make sure you bounce back.

The GMAT, like life, guarantees that you’ll get knocked down a few times, but what you can control is how you respond. Accept the fact that you’re going to take your fair share of Ls, but if you’re a real one you know how to bounce back.

*Getting ready to take the GMAT? We have free online GMAT seminars running all the time. And as always, be sure to follow us on Facebook, YouTube, Google+ and Twitter!*

*By Brian Galvin.*

The post GMAT Tip of the Week: Big Sean Says Your GMAT Score Will Bounce Back appeared first on Veritas Prep Blog.

]]>The post Quarter Wit, Quarter Wisdom: When Can You Divide by a Variable? appeared first on Veritas Prep Blog.

]]>For example:

Is division by x allowed here: x^2 = 10x?

Is division by x allowed here: y = 4x?

Is division by x allowed here: x^2 < 4x?

Let’s take a detailed look at all these questions today.

The basic guidelines:

- Division by 0 is not allowed, hence you cannot divide by a variable until and unless we know that it cannot be 0.
- In the case of an inequality, when you divide by a negative number, the sign of the inequality flips. So we cannot divide by a variable until and unless we know that it cannot be 0 AND whether it is positive or negative.

Let’s look at the three questions given above and try to solve them using these guidelines:

*Is division by x allowed here: x^2 = 10x?*

The first thing to find out here is whether or not x can equal 0.

Case 1: If no other information has been given, then x can be 0 and we cannot divide by it. This is how we proceed in that case:

x^2 – 10x = 0

x(x – 10) = 0

x = 0 or 10

Case 2: If the question stem tells us that x is not 0, then we can divide by x.

x^2/x = 10x/x

x = 10

Obviously, we don’t get the second solution (x = 0) in this case, as we already know that x cannot be 0. Now let’s look at the second problem:

*Is division by x allowed here: y = 4x?*

Again, this is an equation and we need to know whether or not x can equal 0.

Case 1: If x can be 0, you cannot divide by it. In this case, x = 0 and y = 0 is one of the infinite possible solutions.

Case 2: If the question stem states that x cannot be 0, then we can do the following:

y/x = 4

Now let’s look at the final question:

*Is division by x allowed here: x^2 > -4x?*

Here, we have an inequality. Before deciding whether we can divide by x or not, we need to know not only whether x can be equal to 0, but also whether x is positive or negative.

Case 1: If we know nothing about the possible values that x can take, then this is how we proceed:

x^2 + 4x > 0

x(x + 4) > 0

Now we can use the method discussed in the first problem to arrive at the range of x.

x > 0 or x < -4

Case 2: If we know that x is positive, then we can proceed like this:

x^2/x > -4x/x

x > -4

Since we are given that x is positive, we know that that x > 0 (looking at the two options above).

Case 3: If we know that x is negative, then this is how we will proceed:

x^2/x < -4x/x (we flip the sign of the inequality because we divide by x, which is negative)

x < -4

The results obtained are logical, right? When x can be anywhere on the number line, we get the range as x > 0 or x < -4.

If x has to be positive, the range is x > 0.

If x has to be negative, the range is x < -4.

*Getting ready to take the GMAT? We have free online GMAT seminars running all the time. And, be sure to follow us on Facebook, YouTube, Google+, and Twitter!*

*Karishma, a Computer Engineer with a keen interest in alternative Mathematical approaches, has mentored students in the continents of Asia, Europe and North America. She teaches the **GMAT** for Veritas Prep and regularly participates in content development projects such as this blog!*

The post Quarter Wit, Quarter Wisdom: When Can You Divide by a Variable? appeared first on Veritas Prep Blog.

]]>The post GMAT Tip of the Week: Evolving Your GMAT Quant Score with Help from The Evolution Of Rap appeared first on Veritas Prep Blog.

]]>The video below (which is absolutely worth a watch during a designated study break) explores the way that rap has evolved from simple rhyme schemes (yada yada yada Bat, yada yada yada Hat, yada yada yada Rat, yada yada yada Cat…) to the more complex “wait did he just say what I thought he said?” inside-out rhyme schemes that make you rewind an Eminem or Kendrick Lamar track because your ears must be playing tricks on you.

And if you don’t have the study break time right now, we’ll summarize. While a standard rhyme might have a one-syllable rhyme at the end of each bar (do you like green eggs and HAM, yes I like them Sam I AM), rappers have continued to evolve to the point where nowadays each bar can contain multiple rhyme schemes. Consider Eminem’s “Lose Yourself”:

*Snap back to reality, oh there goes gravity*

* Oh there goes Rabbit he choked, he’s so mad but he won’t*

* Give up that easy, nope, he won’t have it he knows*

* His whole back’s to these ropes, it don’t matter he’s dope*

* He knows that but he’s broke, he’s so stagnant he knows…*

Where “gravity,” “Rabbit, he,” “mad but he,” “that easy,” “have it he,” “back’s to these,” “matter he’s,” “that but he’s,” and “stagnant, he” all rhyme with one another, the list of goes/goes/choked/so/won’t/knows/whole/ropes/don’t/dope… keeps that hard “O” sound rhyming consistently throughout, too. And that was 15 years ago…since them, Eminem, Kendrick, and others have continued to build elaborate rhyme schemes that reward those listeners who don’t just listen for the simple rhyme at the end of each bar, but pick up the subtle rhyme flows that sometimes don’t come back until a few lines later.

So what does this have to do with your GMAT score?

One of the most common study mistakes that test-takers make is that they study skills as individual, standalone entities, and don’t look for the subtle ways that the GMAT testmaker can layer in those sophisticated Andre-3000-style combinations. Consider an example of an important GMAT skill, the “Difference of Squares” rule that (x + y)(x – y) = x^2 – y^2. A standard (think early 1980s Sugarhill Gang or Grandmaster Flash) GMAT question might test it in a relatively “obvious” way:

*What is the value of (x + y)?*

*(1) x^2 – y^2 = 0*

*(2) x does not equal y*

Here if you factor Statement 1 you’ll get (x + y)(x – y) = 0, and then Statement 2 tells you that it’s not (x – y) that equals zero, so it must be x + y. This Data Sufficiency answer is C, and the test is essentially just rewarding you for knowing the Difference of Squares.

*The GMAT it cares
’bout the Difference of Squares
When there’s squares and subtraction
Put this rule into action*

A slightly more sophisticated question (think late 1980s/early 1990s Rob Bass or Run DMC) won’t so obviously show you the Difference of Squares. It might “hide” that behind a square that few people tend to see as a square, the number 1:

*If y = 2^(16) – 1, the greatest prime factor of y is:*

*(A) Less than 6*

* (B) Between 6 and 10*

* (C) Between 10 and 14*

* (D) Between 14 and 18*

* (E) Greater than 18*

Here, many people don’t recognize 1 as a perfect square, so they don’t see that the setup is 2^(16) – 1^(2), which can be factored as:

(2^8 + 1)(2^8 – 1)

And that 2^8 – 1 can be factored again, since 1 remains 1^2:

(2^8 + 1)(2^4 + 1)(2^4 – 1)

And that ultimately you could do it again with 2^4 – 1 if you wanted, but you should know that 2^4 is 16 so you can now get to work on smaller numbers. 2^8 is 256 and 2^4 is 16, so you have:

257 * 17 * 15

And what really happens now is that you have to factor out 257 to see if you can break it into anything smaller than 17 as a factor (since, if not, you can select “greater than 18”). Since you can’t, you know that 257 must have a prime factor greater than 18 (it turns out that it’s prime) and correctly select E.

The lesson here? This problem directly tests the Difference of Squares (you don’t want to try to calculate 2^16, then subtract 1, then try to factor out that massive number) but it does so more subtly, layering it inside the obvious “prime factor” problem like a rapper might embed a secondary rhyme scheme in the middle of each bar.

But in really hard problems, the testmaker goes full-on Greatest of All Time rapper, testing several things at the same time and rewarding only the really astute for recognizing the game being played. Consider:

*The size of a television screen is given as the length of the screen’s diagonal. If the screens were flat, then the area of a square 21-inch screen would be how many square inches greater than the area of a square 19-inch screen?*

*(A) 2*

* (B) 4*

* (C) 16*

* (D) 38*

* (E) 40*

Now here you KNOW you’re dealing with a geometry problem, and it also looks like a word problem given the television backstory. As you start calculating, you’ll know that you have to take the diagonal of each square TV and use that to determine the length of each side, using the 45-45-90 triangle ratio, where the diagonal = x√2. So the length of a side of the smaller TV is 19/√2 and the length of a side of the larger TV is 21/√2.

Then you have to calculate the area, which is the side squared, so the area of the smaller TV is (19/√2)^2 and the area of the larger TV is (21/√2)^2. This is starting to look messy (Who knows the squares for 21 and 19 offhand? And radicals in denominators never look fun…) UNTIL you realize that you have to subtract the two areas. Which means that your calculation is:

(21/√2)^2 – (19/√2)^2

This fits perfectly in the Difference of Squares formula, meaning that you can express x^2 – y^2 as (x + y)(x – y). Doing that, you have:

[(21 + 19)/√2][(21-19)/√2]

Which is really convenient because the math in the numerators is easy and leaves you with:

(40/√2) * (2/√2)

And when you multiply them, the √2 terms in the denominators square out to 2, which factors with the 2 in the numerator of the right-side fraction, and everything simplifies to 40. And then, in classic “oh this guy’s effing GOOD” hip-hop style (like in the Eminem lyric “you’re witnessing a massacre like you’re watching a church gathering take place” and you realize that he’s using “massacre” and “mass occur” – the church gathering taking place – simultaneously), you realize that you should have seen it coming all along. Because when you subtract the area of one square minus the area of another square you’re LITERALLY taking the DIFFERENCE of two SQUARES.

So what’s the point?

Too often people study for the GMAT like they’d listen to 1980s rap. They expect the Difference of Squares to pair nicely at the end of an Algebra-with-Exponents bar, and the Isosceles Right Triangle formula to pair nicely with a Triangle question. They learn skills in distinct silos, memorize their flashcards in nice, tidy sets, and then go into the test and realize that they’re up against an exam that looks a lot more like a 2017 mixtape with layers of rhyme schemes and motives.

You need to be prepared to use skills where they don’t seem to obviously belong, to jot down and rearrange your scratchwork, label your unknowns, etc., looking for how you might reposition the math you’re given to help you bring in a skill or concept that you’ve used countless times, just in totally different contexts. The GMAT testmaker has a much more sophisticated flow than the one you’re likely studying for, so pay attention to that nuance when you study and you’ll have a much better chance of keeping your score 800.

**free online GMAT seminars **running all the time. And as always, be sure to follow us on **Facebook**, **YouTube**, **Google+** and **Twitter**!

*By Brian Galvin.*

The post GMAT Tip of the Week: Evolving Your GMAT Quant Score with Help from The Evolution Of Rap appeared first on Veritas Prep Blog.

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]]>Let’s explore this idea through an example GMAT data sufficiency question:

*What is the standard deviation of a set of numbers whose mean is 20?*

*Statement 1: The absolute value of the difference of each number in the set from the mean is equal.*

*Statement 2: The sum of the squares of the differences from the mean is greater than 100.*

We need to determine whether the information we have been given is sufficient to get us the exact value of the standard deviation of a particular set of numbers. To find the standard deviation of a set, we need to know the deviation of each term from the mean so that we can square those deviations, sum the squares, divide them by the number of terms, and then find the square root.

Essentially, to find the standard deviation we either need to know each element of the set, or we need to know the deviation of each element from the mean (which will also give us the number of terms), or we need to know the sum of the square of deviations and the number of terms in the set.

The question stem here tells us that the mean of the set is 20. We have no other information about any of the actual elements of the set or the number of elements. With this in mind, let’s examine each of the statements:

Statement 1: The absolute value of the difference of each number in the set from the mean is equal.

With this statement, we don’t actually know what the absolute value of the difference is. We also don’t know how many elements there are. The set could be something like:

19, 21 (each term is exactly 1 away from the mean 20)

or

18, 18, 22, 22 (each term is exactly 2 away from the mean 20)

etc.

The standard deviation in each case will be different. We don’t know the elements of the set and we don’t know the number of elements in the set. Because of this, there is no way for us to know the value of the standard deviation – this statement alone is not sufficient.

Statement 2: The sum of the squares of the differences from the mean is greater than 100.

“Greater than 100” encompasses a large range of numbers – it could be any value larger than 100. Again, we cannot find the exact standard deviation of the set, so this statement is also not sufficient alone.

Using both statements together, we still do not have any idea of what the elements of the set are or what the sum of the squares of the differences from the mean is. We also still don’t know the number of elements. Hence, both statements together are not sufficient, so the answer is E.

Now, let us add just one more piece of information to the problem in this similar question:

*What is the standard deviation of a set of 7 numbers whose mean is 20?*

*Statement 1: The absolute value of the difference of each number in the set from the mean is equal.*

*Statement 2: The sum of the squares of the differences from the mean is greater than 100.*

What would you expect the answer to be? Still E, right? The sum of the deviations are still unknown and the exact elements of the set are still unknown – all we know is the number of elements. Actually, this information is already too much. All we need to know is that the number of elements is odd and suddenly we can find the standard deviation.

Here is why:

Statement 1 is quite tricky.

If we have an odd number of elements, in which case can the absolute values of the differences of each number in the set from the mean be equal?

Think about it – the mean of the set is 20. What could a possible set look like such that the mean is 20 and the absolute values of the differences of each number in the set from the mean are equal. Try to think of such a set with just 3 elements. Can you come up with one?

19, 19, 21? No, the mean is not 20

19, 20, 21? No, the absolute value of the difference of each number in the set from the mean is not equal. 19 is 1 away from mean but 20 is 0 away from mean.

Note that in this case, the only possible set that could fit the given criteria is one consisting of just an odd number of 20s (all elements in this set must be 20). Only then can each number be equidistant from the mean, i.e. each number would be 0 away from mean. If the numbers of the set all have equal elements, then obviously the standard deviation of the set is 0. It doesn’t matter how many elements it has; it doesn’t matter what the mean is! In this case, Statement 1 alone is sufficient so the answer would be A.

**Takeaway**:

If a set has an even number of distinct terms, the absolute values of the distances of each term from the mean could be equal. But if a set has an odd number of terms and the absolute values of the distances of each term from the mean are equal, all the terms in the set must be the same and will be equal to the mean.

**free online GMAT seminars** running all the time. And, be sure to follow us on **Facebook**, **YouTube**, **Google+**, and **Twitter**!

*GMAT** for Veritas Prep and regularly participates in content development projects such as this blog!*

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]]>*Alice’s take-home pay last year was the same each month, and she saved the same fraction of her take-home pay each month. The total amount of money that she had saved at the end of the year was 3 times the amount of that portion of her monthly take-home pay that she did NOT save. If all the money that she saved last year was from her take-home pay, what fraction of her take-home pay did she save each month?*

*(A) 1/2*

*(B) 1/3*

*(C) 1/4*

*(D) 1/5*

*(E) 1/6*

Let’s consider the question stem sentence by sentence:

“Alice’s take-home pay last year was the same each month, and she saved the same fraction of her take-home pay each month.”

Say Alice’s take-home pay last year was $100 each month. She saves a fraction of this every month – let the amount saved be x.

“The total amount of money that she had saved at the end of the year was 3 times the amount of that portion of her monthly take-home pay that she did NOT save.”

What would be “the total amount of money that she had saved at the end of the year”? Since Alice saves x every month, she would have saved 12x by the end of the year.

What would be “the amount of that portion of her monthly take-home pay that she did NOT save”? Note that this is going to be (100 – x). Many test takers end up using (100 – x)*12, however this equation is not correct. The key word here is “monthly” – we are looking for how much Alice does not save each month, not how much she does not save during the whole year.

The total amount of money that Alice saved at the end of the year is 3 times the amount of that portion of her MONTHLY take-home pay that she did not save. Now we know we are looking for:

12x = 3*(100 – x)

x = 20

“If all the money that she saved last year was from her take-home pay, what fraction of her take-home pay did she save each month?”

From our equation, we have determined that Alice saved $20 out of every $100 she earned every month, so she saved 20/100 = 1/5 of her take-home pay.

Therefore, the answer is D.

Often, test-takers make the mistake of writing the equation as:

12x = 3*(100 – x)*12

x = 300/4

However, this will give them the fraction (300/4)/100 = 3/4, and that’s when they will wonder what went wrong.

Be extra careful when reading GMAT questions so that precious minutes are not wasted on such avoidable errors.

**free online GMAT seminars** running all the time. And, be sure to follow us on **Facebook**, **YouTube**, **Google+**, and **Twitter**!

*GMAT** for Veritas Prep and regularly participates in content development projects such as this blog!*

The post Quarter Wit Quarter Wisdom: How to Read GMAT Questions Carefully appeared first on Veritas Prep Blog.

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