GMAT & MBA Admissions Blog

Logical estimation might be the single most important tactic for GMAT problem solving questions in the quantitative reasoning portion of the GMAT. We’ve already written an article that covers GMAT problem solving questions and strategies more generally, so we recommend you take a moment to read that before continuing if you haven’t yet. Moving forward, this article will address the following key topics:

● A general description of quantitative logical estimation and the conditions under which it should be utilized
● An overview of the strategic implications of logical estimation
● An example of logical estimation in the context of arithmetic
● An example of logical estimation in the context of word problems
● A summary of the logical estimation problem solving process

Quantitative Logical Estimation

Simply put, logical estimation refers to the process of continuously eliminating impossible answer choices as you tackle a problem. As any online GMAT tutor will tell you, it is one of the most important strategies to employ on the GMAT. In other words, thinking critically about what must be false in addition to what must be true can make the difference between an average score and a great score. Not only will this strategy save you time, but it will also allow you to maintain laser focus as you work through the problem-solving section of the test. More specifically, this method is especially useful when a question asks you to seek a range or approximation rather than a specific value.

To effectively implement the logical estimation process, one of your fist considerations as you read through a problem should be where the viable answer falls within the following binaries:

● Positive or negative
● Even or odd
● Integer or non-integer
● Factor or non-factor
● High or low

For example, if the question makes it clear that the correct answer must be even, you can immediately discount all answer choices that are odd–thereby increasing the likelihood of selecting the correct answer.

Strategic Implications

In addition to the binary-based elimination strategy mentioned above, you would be well advised to take the following strategic measures:

● Consciously note your choices at the beginning of the problem for estimation considerations
● Stop and select the correct choice if through estimation only one answer remains viable
● Avoid blindly guessing by using logical estimation until you’ve been stuck for 20 seconds without progressing
● Make note of key terms such as “Approximate” or “Closest to,” as they indicate cases in which logical estimation could be your primary problem-solving tactic.

Arithmetic Example

Question:

104 - 94 is closest to:
A. 1
B. 100
C. 1,000
D. 3,500
E. 6,500

Logical Estimation Process:

1. Set up a scratch pad listing choices vertically from A to E

2. Note inexact sought value and label choices as such
● 104 - 94 is closest to ?

3. Read from the beginning, taking notes and noting logical estimation opportunities to avoid unnecessary calculations
● Eliminate A, B, C
● 94 = 92 x 92 = 81 x 81
● Approximate as 80 x 80 = 6,400
● 10,000 – 6,400 = 3,600
● Select Choice D
● Beware of Too Fast Trap Choice E

Word Problem Example

Question:

If set N is comprised solely by each of the prime numbers less than 20, and the sum of the reciprocals of the terms in set N is a, what must be true of a?
A. a < 0
B. a < ½
C. a < 1
D. 1 < a < 2
E. 2 < a

Logical Estimation Process:

1. Set up a scratch pad listing choices vertically from A to E

2. Note inequalities in choices, not a single numeric value and label choices as such
● What must be true of a?

3. Read from the beginning, taking notes and noting logical estimation opportunities to avoid unnecessary calculations
● List Prime Numbers < 20 as 2, 3, 5, 7, 9, 11, 13, 15, 17, 19
● Note Reciprocals as 1 over each of the terms (ie. ½, ⅓, ⅕, etc.)

4. Work through the problem while consciously considering logical estimation as your primary tactic
● Use common fractions to decimal conversions to determine that ½ + ⅓ + ⅕ = 0.5 + 0.333 + 0.2 > 1
● Eliminate choices A, B, and C
● Note only seven terms remain each ≤ ⅐ remaining sum < 1
● Eliminate E and select choice D!

Summary of Logical Estimation Problem Solving Process

1. Set up a scratch pad listing choices vertically from A to E
● Note large numeric differences or ranges in choices

2. Skip to the end of the problem and label choices as sought value(s)
● Note if seeking a non-specific value

3. Read from the beginning, taking notes and doing needed calculations
● Seek time saving opportunities by not fully calculating

4. Work through the problem while using chosen tactic until one choice remains viable
● Eliminate impossible choices as you go to expedite the process!

If you are looking for more advice, consider requesting a 1-1 consultant with an expert GMAT tutor.

An 80^th percentile GMAT quant score is said to be necessary to get admitted to many of the top MBA programs in the U.S. Is this true? Who knows? I went to the Kellogg School of Management, but scored below the 80^th percentile on GMAT quant. That said, it certainly helps and is an excellent GMAT score goal. Do you want to score above the 80^th percentile on GMAT quant? 

Although preparing for the GMAT requires a sizeable investment of your time and money, doing so will increase your chances of being accepted into top MBA programs with high-earning job placements—not to mention receiving significant academic scholarships. With this in mind, one of the most effective ways to ensure a stellar performance on the GMAT is to hire a personal tutor. Because anyone can present themselves as a “qualified” tutor regardless of experience level, it’s your responsibility to make sure you choose wisely. To make your decision a little easier, we’ve listed 5 non-negotiable traits an effective tutor must have. Keep these in mind as you embark upon your search!

1. High GMAT Score

Perhaps it goes without saying that you should only place your trust in the hands of someone who knows what it takes to achieve a high score on the GMAT. Generally speaking, a qualified GMAT tutor will have scored at least in the 99th percentile. If a tutor’s resume doesn’t include this critical information, don’t be afraid to ask! More specifically, an ideal tutor will demonstrate equal mastery of all four sections of the GMAT: analytical writing, integrated reasoning, quantitative reasoning, and verbal reasoning. You don’t want to end up with a tutor who excels at some, but not all of these key elements.

2. Tutoring Experience

Though there is certainly some overlap between the two, performing well on the GMAT does not guarantee that someone can teach it well. In other words, just because someone knows how to take the test doesn’t mean they have the skills necessary to clearly explain their methodology to others. For this reason, it isn’t enough for a potential tutor to have a stellar score. It is equally if not more critical that your tutor have significant experience teaching the GMAT. Some clear indicators of a tutor’s credibility include the number of students they’ve taught and the duration of time they’ve been doing so.

3. Student Centered

If you were looking for a one-size-fits-all approach, you would have opted for an alternative that’s cheaper than tutoring—like a textbook, a prep course, or an online app. If you encounter a tutor that uses the same methodology on all of their clients, you should therefore run the other way. A skilled tutor knows how to assess a student’s particular strengths and weaknesses and utilizes that information to build a unique study plan that caters to their needs. For this reason, make sure you find a tutor that demonstrates a commitment to understanding your unique goals, study habits, and challenges. A tutor who fails to ask questions about your thoughts, questions, and concerns is not worth paying for.

4. Location and Availability

The most practical consideration to make pertains to your schedule. Before you begin your search for a tutor, make note of your weekly availability as well as the maximum distance you’re willing to travel for in-person meetings. If you live in a relatively isolated area, or if you simply do not have the time to commute, consider the option of online tutoring. With the development of applications like Skype, Zoom, and Teams, there are a few things that can’t be accomplished remotely. So long as your tutor is available at the same times as you, distance shouldn’t be a serious impediment.

5. Passion for Subject Matter

Have you ever taken a class about a subject you thought you hated, only to have your teacher’s unbridled passion rub off on you? This is because enthusiasm is contagious. Although standardized tests don’t usually arouse excitement in most people, you might be surprised to know how much the best tutors care about the subject matter. A tutor who is passionate about teaching will resonate on a different level than a tutor whose only in it for the money. You would therefore be well advised to work with a tutor who is passionate not only about the GMAT, but also about sharing that passion as a means of empowering their students.

In conclusion, trust your gut. A tutor who genuinely sees your potential will make you see your own potential in a new light as well. It’s also worth noting that you have the right to take potential tutors for a trial run before making any commitments. If you still feel like you need more information, feel free to ask for references from previous clients. If a tutor is not willing to comply with these requests, walk away. When your hard earned money is at stake, don’t settle for anything less than a qualified, professional, attentive, and passionate tutor.

Although the concepts covered in the GMAT are quite simple, do not be fooled. The test is designed to assess your ability to identify patterns and problem-solve in subtle, sophisticated ways—all under the pressure of the clock. No matter how smart you are, the unique ways in which the GMAT tests analytical, writing, quantitative, verbal, and reading skills require serious preparation. With this in mind, developing an intentional study plan plays a crucial role in the process of attaining a competitive score. Rather than blindly opening a textbook or half-heartedly starting a prep class, you would be well advised to first think critically about your particular goals and how best to attain them. To inform your study plan, we’ve summarized 5 key steps to keep in mind.

1. Compare Your Raw Score to Your Target Score

Before you even begin taking steps to improve your test-taking ability, it’s important to understand how your raw score stacks up to your target score. Just as a soccer player adjusts the angle and power of a kick depending on their relative position to the goal, so too must a test-taker define the duration and intensity of their study plan relative to the target score. This is to say that without an understanding of where you’re aiming, a clear plan of action is much more elusive. Comparing your raw score to your target score is also important in the sense that it will enable you to identify your strengths and weaknesses early on. A soccer player with a strong defense and a weak offense would be imprudent to spend equal amounts of time improving each. Similarly, a student who excels in the verbal, writing, and reading portions of the GMAT but struggles when it comes to its analytical and quantitative components would be wise to adjust their study plan to prioritize the development of their weaknesses.

2. Choose the Prep Method that Best Caters to Your Individual Needs

After you’ve determined the distance you need to cover as well as the particular areas that need the most improvement to get you there, you’ll be ready to choose an appropriate prep method. Whether it be through a simple textbook, a self-paced app, an in-person or online course, or a private tutor, make sure that your method of choice reflects your particular needs. Students who are able to stay motivated without the accountability and structure that most prep courses and tutors provide are more likely to thrive through self-study methods supplemented by prep books and online applications (like Magoosh or Khan Academy). On the other hand, those who absorb information best with the guidance only a teacher can provide, especially if they have a lot of improvements to make, would be wise to take a prep course or work with a private tutor. Regardless of which study method you choose, always make sure that you are continuously maintaining and adjusting a personal curriculum to reflect your strengths and weaknesses.

3. Define your Study Timeline

It is often assumed that the more time you give yourself to prepare, the better. While this is generally true, needlessly stretching out the duration of your study plan is not necessarily the most effective way to manage your time. Studying with laser-focused attention over a shorter, more clearly defined period of time is much more efficient than distractedly reviewing material throughout a longer and vaguer period. Of course, this isn’t to suggest that you should only give yourself a few weeks to study. Generally speaking, devoting 10-15 hours a week for about 10 weeks will do the trick. It is also important to be strategic about when you carve out your study timeline. Devoting 10 weeks of disciplined study time will be much more challenging during a time of your life in which you’re working a 9 to 5 job. For this reason, try to carve out a study timeline during a transitional phase of your life. Whether it be during the window between graduating from college and finding a new job, changing from one job to another, or any other extended time off you may be able to take, seize the opportunity to really double down on your GMAT prep.

4. Adhere to Deliberate Practice Principles

Any good GMAT tutor wants his or her student to review GMAT homework as efficiently as possible. Careful review of missed GMAT problems is one of the most critical parts of GMAT test prep. So what are our best tips for students as they review missed problems on GMAT practice tests?

Is a GMAT tutor worth it?

Since I am writing this on a GMAT blog hosted by a GMAT tutoring company, you might expect me to say that unequivocally, a GMAT tutor is worth it. But the answer is clearly “it depends.”