GMAT Tip of the Week: Don't Arrest Your Development

There are many memorable things happening this Memorial Day weekend, but perhaps none is as exciting as the much-anticipated return of Arrested Development, the cult classic sitcom re-premiering on Netflix on Sunday. Panned by the masses in large part because it’s humor was “too smart,” Arrested Development can provide some useful intelligence to aid in your own GMAT development. So if the GMAT has you down this beginning-of-summer weekend, there’s no need to hide in your Aztec tomb, join a blue man group for moral support, or hide your lack of GMAT confidence behind cutoff shorts. We don’t think you’re a chicken (coo-coo-ca-cha!). Arrested Development is here to teach you an important lesson – and this time it’s not J. Walter Weatherman, but instead the former President of the Bluth Company, Gob.

Gob Bluth is famous for his hatred of the word “trick,” (don’t call it that) in favor of the word “illusion.” Tricks he casts off as beneath him, whereas illusions seem more sophisticated for an elite magician. And you shouldn’t simply accept tricks, either – if you look deeper (as Tony Wonder would say, you can try to use your illusion) you’ll find that a more sophisticated, deeper understanding of tricks will help you gain acceptance from the Magicians Alliance or the business school of your choice. Here’s how:

Many a GMAT student will learn a rule from the solution to a problem and understand exactly how to apply it to *that* problem. But the GMAT – like a good magician – is a master of misdirection. You’ll seldom see that exact same problem structure again, so if all you know is how to apply that rule – that “trick” – in that one context you’ll be disappointed and frustrated when you see questions that look like nothing you’ve ever seen. But if you understand the rule and why it works – if you look deeper than the trick and see it as more than a single-use process – you’ll have fuller control of it in the future.

For example, it’s pretty common among GMAT students to memorize the “trick”: “If it’s an inclusive set you add 1″. And that’s because in a problem like:

What is the sum of all the integers between 10 and 50, inclusive?

You need to know how many terms there are. And the “inclusive” rule is that you take the difference (50 – 10 = 40) and add one to determine the number of terms. There are 41 terms, and the average of the terms is 30, so the correct answer is 41*30 = 1230.

But here’s where the trick can lead you astray. The word “inclusive” itself doesn’t always mean “add one.” There are many contexts in which a question could us the word “inclusive” and not be testing that rule/trick. Here’s why the rule works: Consider “how many integers are between 1 and 3, inclusive”. If you’re including both 1 and 3, you can just count them out: 1, 2, and 3 leads you to 3 integers. Because you’re including each of the endpoints, the range (2) will be one less than the number of integers (3). You have to add one to get from the range to the number of integers.

But here’s another “inclusive” question in which blindly adding one would lead you astray:

If m is the product of all the integers from 3 to 11, inclusive, how many different prime numbers are factors of m?

Notice – this problem is not asking you to determine how many integers are in that set!! The word “inclusive” just means that you have to include 3 and 11 in your work – 11 is a prime factor of m (whereas it wouldn’t be had the question said “exclusive”). To solve this one, you’ll want to check the primes of all the numbers that multiply to form m:

3 * 4 * 5 * 6 * 7 * 8 * 9 * 10 * 11

= 3 * (2*2) * 5 * (2*3) * 7 * (2*2*2) * (3*3) * (2*5) * 11

Then count up the different primes: 2, 3, 5, 7, and 11 lead you to the answer 5.

So what can you learn from this?

Simply memorizing rules as “tricks” can leave you vulnerable to GMAT misdirection. It’s not enough to simply memorize tricks – you should aim to understand them as principles so that you can determine when it’s helpful to apply them and when they may not apply. “Inclusive” doesn’t mean “add one” in all circumstances – the reason you’d add one is if you’re able to calculate the range and want to know the number of terms within it. “Inclusive” really just means “the first and last number are part of the calculation,” but since a couple of problems in the Official Guide for GMAT Review and other study resources allow you to use the “inclusive –> add one to find the number of terms” trick, many students simply memorize that trick as a knee-jerk reaction.

But like Gob Bluth protests, tricks are a little too juvenile and crude for someone with higher aspirations. Tricks can arrest your development, keeping you from being able to solve the higher-level, reasoning-based questions that higher scorers see plenty of. Don’t be satisfied simply memorizing tricks, but instead try to understand why the rules work conceptually and when they do/don’t apply. Transcend tricks and raise your score.

…and that’s why you always leave a note.

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