GMAT Advice From a 770 MBA

The GMAT Prep Crunch

The GMAT prep crunch

“Real knowledge is to know the extent of one’s ignorance.” – Confucius

Talk to friends who are just starting out on the path to the GMAT, and you will hear resounding gripes and grievances of, “I had no idea how much I didn’t know.” Most people in this position have been in the workforce for three to five years, have had great career success and felt confident enough in their own intellect to make a $100,000 investment (i.e. business school). So, naturally, it can bruise the ego when you’re reintroduced to rusty concepts, such as geometry and quadratics, which seem a lot harder than in high school.

But the GMAT isn’t testing the same type of geometry and quadratics you did in high school, and, quite frankly, you probably don’t know how to do the kind of math the sacred 700+ GMAT score requires. It’s not a test of your computational abilities – if it were that easy, the average student wouldn’t dish out $1,000 or more on test prep. The test makers use familiar concepts but make them much more difficult with one purpose in mind: to assess your ability to think through problems (similar to those you’ll meet in the business world) quickly, accurately and efficiently. Consider the following problem:

If x is a positive integer, is (x)(x+2)(x+4) divisible by 12?

(1) x² + 2x is a multiple of 3

(2) 3x is a multiple of 2

The set-up of a Data Sufficiency question alone is something unique to the GMAT. You are given a question stem (the phrase above the two statements) and you must determine whether or not the information in either, both combined or neither of the statements is sufficient to solve the problem. This type of critical thinking is not about simply solving the problem but determining the minimal unknown data you would need to be able to solve it.

Given ten minutes you might be able to come up with an answer using your memory of high school math, but under time restrictions of 1½ to 2 minutes per question, it’s not enough to know how to do the math eventually – you need to know how to do the math efficiently. Here’s a breakdown of the strategic thinking and approach that will get to the answer quickly and confidently:

Analyze the Question

What is the question type?

o This is a Data Sufficiency question

o Within the Data Sufficiency question type, there are two sub-types: Yes/No and Value. This is a Yes/No question type – always yes, divisible by 12 or always no, not divisible by 12

What is the area of knowledge being tested?

o Our familiarity with Number Properties

State the Task

We need to find out if the information in the statements is sufficient to determine whether the statement (x)(x+2)(x+4) will always – or always not – be divisible by 12.

Approach Strategically

Whenever you see “divisible by” you should automatically break the number in question (in this case, 12) down to its prime factors. This is a pattern recognition that will help you ultimately save time on similar questions on test day. Getting the number in question to its prime factors will allow you to see if those same prime factors are present in the statement at hand much more easily. If they are, then any additional factors are only multiplying 12 by a greater amount. This is the type of strategic thinking you will need on the GMAT, rather than the long division you were taught in high school.

For example: 12 = 2 x 2 x 3, so we know that in order for the statement (x)(x+2)(x+4) to be divisible by 12 it must include those same prime factors. Any additional factors in the makeup of (x)(x+2)(x+4) will only be multiplying 12 by a greater amount (and therefore will still be divisible by 12).

Now that we understand the basic goal of this problem is to find out if there is a 2 x 2 x 3 somewhere in the statement (x)(x+2)(x+4), we have a much clearer picture of the exact information we are looking for as we go into evaluating the statements.

Statement (1) says that x² + 2x is a multiple of 3. The “x²” here should be a red flag that you will need to factor out the quadratic (x)(x+2)(x+4) to get it into the same terms. By multiplying the first two sets of parenthesis we get (x² + 2x)(x+4). Look familiar? So now we know that the first parenthesis is a multiple of 3 (one of our prime factors we are looking for) – great. But we still know nothing about the second set of parenthesis (x+4). If (x+4) includes a 2 x 2 then we will have all three prime factors needed. But if it does not, then it will not be a multiple of 12. Since we have no way of knowing, Statement (1) is insufficient.

Remember to never let any information you gained from Statement (1) influence your decision as you move on to evaluate – separately – Statement (2).

Statement (2) says that 3x is a multiple of 2. We know that 3 is not a multiple of 2, so that means that x must be. Let’s start simply with x = 2. If we plug that back into our original statement we have (2)(2+2)(2+4) = (2)(4)(6) = 2 x 2 x 2 x 2 x 3. We have all prime factors (2 x 2 x 3) to make this number divisibly by 12, and any larger multiple of 2 that x could equal would only make the multiplication of 12 larger (and still yes, always divisible by 12). Statement (2) is sufficient and we are ready to confidently move on to the next problem.

As you can see, the type of math that you will need to ace the GMAT is more about strategy and pattern recognition than it is doing the math itself. All of the numbers we were working with in this example were very small and easily manageable. However, if you didn’t have the strategies and shortcuts, you would be stuck working with much larger numbers and taking much more time than you should be.

Needless to say, the test prep process can be very discouraging as you realize that the standard math you learned in high school won’t cut it. Unfortunately for some the GMAT can become a major obstacle, and unless you are a genius, it is most probable that you will be met with self-doubt along the way. But as Confucius was so astute to point out, “Real knowledge is to know the extent of one’s ignorance.” The realization of how much we do not yet know can discourage us. But if you want to be successful on the GMAT, it is that same discouragement that gives definition to your areas of opportunity for better understanding – and ultimately – to that prized 700+ test score.

Saxon McClintock is a professional GMAT tutor for Varsity Tutors. She earned a BS in Business Administration from Pepperdine University and is currently an MBA candidate at UCLA Anderson. She scored a 770 on the GMAT.

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  • Guest

    Kaplan is the best

  • Bob

    I am currently weighing my options as to which GMAT Prep company to go through. Would anyone be able to provide any insight on their experience?

    Thanks in advance.


  • morning_in_america

    All this expensive coaching and test prep. It’s like an arms race. It was so much simpler in the ’80s when a $7 book of practice tests was all I needed for a GMAT score to get into a top 5 B-School.

  • Tommy

    Oops. Meant to say that to you here. Allen is a classic misogynist. Annoying.

  • Tommy

    Agreed. I can’t stand bullshit like this. What a jerk.

  • Laura

    Top tier generally refers to programs who are consistently in the top 10. I’m confused as to what your judgement of her physical attributes has to do with anything in my comment and why it would be brought up as the leading adjective when making an assessment about her qualification for an MBA program. As I said, I am sure she is more than capable of assessing her options and made the right decision for her, and does not need someone white-knighting her on an editorial publication she wrote by making comments about her looks. Its very unlikely you would have responded by leading with “he is absolutely handsome with a great personality…” if the subject in the article was a male. Perhaps you should evaluate how you assess and define your female peers. All I said was that merely having a high GMAT score does not assure a top tier placement anymore. I said nothing to imply she was unattractive, lacked personality, or lack work ethic, so it is perplexing as to why anyone would feel the need to defend her on these items. I’m sure this was a knee-jerk reaction defending your friend against perceived criticism, but you do your friend and other female MBAs a disservice.

  • Allen

    Anderson is a great school. I know this girl personally; she is absolutely gorgeous with a great personality and excellent work experience. Not going to disclose anything else about her, but I am 100% sure she could have gone to a “top tier” (whatever the hell that means) and chose Anderson because of her industry ties to a major world class city like Los Angeles.

  • Laura

    Anderson is an alright school. But lets not pretend there are not considerable differences between “top 15” (which Anderson nearly dropped out of last year and remains precariously on the ledge of) and a top tier program. The opportunities may be “similar” but you they cannot be credibly claimed to be “equal.” Perhaps her professional credentials were a bit lacking for a top tier program. The GMAT still caries considerable weight, but I think more and more, and especially with the inordinate amount of time and money people spend to get a good score, schools are seeing the fact that all it really does is demonstrate a basic capability to take a test and/or study extremely hard to get a good score. Its not really a that good an indicator of professional or intellectual capability. So, while a person who has a 750+ AND considerable professional credentials may be a shoe-in for a top school, having just a 750+ GMAT is really no assurance of anything except a spot in the top 30. In any case, a 770 score isn’t something to scoff at and I’m sure she will do just fine, is more than capable of appropriately assessing her options, and made the right decision for her.

  • imperialmight

    I’m not disputing that, it just struck me as slightly odd. I used to think the GMAT carried more weight in the admissions process.

  • LevFin

    Anderson is a great school. Her decision to attend could have been due to a number of factors including, but not limited to the school’s location or her experience when visiting Anderson.

    In my experience in choosing a full-time MBA program, I have encountered at least two different types of people: those who choose a program based on ranking and those who choose based on other factors such as the campus, students, or curriculum, for example. There are plenty of kids who have attended top undergraduate schools, finished in the top of their class, had great careers, killed the GMAT, and ultimately decided to attend a top 15 program.

    And let’s face it: the real measure of success is after business school, anyway. I’d rather be a billionaire from Anderson than a millionaire from a “top 5 business school.” The opportunities for Anderson kids immediately after graduation are going to be similar to many of those for kids at “better ranked” schools.

  • MBA’er

    @imperialmight:disqus Why would you even take the time to post this? I don’t even go to Anderson and yet I’m baffled by your narrow-minded comment, with all due respect (lol).

  • epony

    It’s just another one of those real life examples that the GMAT is not the be-all and end-all of one’s MBA application…

  • imperialmight

    With a 770 on the GMAT, you’d think that she could do better than Anderson (I say that with all due respect).

  • epony

    Hmm… Having scored a 770 on the GMAT myself, graduated from a global top 5 business school and been a professional GMAT tutor several top notch schools, I would take a much more tactical approach to this question.

    My approach would be to solve the statement for 1 and for 2. Solving for x = 1 would give us 1 x 3 x 5. Solving for x = 2 would give us 2 x 4 x 6. It’s fairly easy to ascertain that solving for 2 gives us a result that is always divisible by 12, while solving for 1 doesn’t.

    Now, let’s look at statements (1) and (2). Statement (1) can be solved by x = 1. However, we’ve already ascertained that the original statement isn’t satisfied by x = 1, so statement (1) is bust. Statement (2) is a multiple of 2 for every even integer, e.g. x = 2. Seeing as we’ve already established that we can determine the original statement for x = 2, then we’re happy with any even integer (since, by definition, they’re all divisible by 2).

    So, a different approach, which I would argue is more straightforward than utilizing prime factors, yields the correct answer. I completely agree with and understand why the author chose to utilize prime factors in this case, but I would tend to save this method to larger numbers than 12. With practice, I would wager that most other GMAT takers would too.