GMAT Tip of the Week: Carving Out A High Score

As we enter the final weekend of the Vancouver Winter Olympics, plenty of drama remains. Will Canada clinch the ice hockey gold medal on its home ice? Will it do so against the rival Americans? Will Lindsey Vonn withstand the pain of another injury - this time a broken finger to go with her badly bruised shin -- to add another medal to her haul? Will Bob Costas ever look older than 29? Will Bode Miller summon the magic one more time to erase his Torino disappointment with an unexpected (or perhaps just delayed... we expected this from him in 2006) display of overall alpine mastery?

As Vonn and Miller attempt to add to their legacies, they will need to employ a strategy that you should be thinking about as you gear up for your peak performance on the GMAT. The last race for each is the slalom, an event in which skiers are required to navigate a series of gates making quick side-to-side turns while keeping their momentum focused as straight downhill as possible. A daunting challenge, to be sure -- just like those of you taking the GMAT, these skiers must be aware that losing time on any one gate (or question) can be catastrophic, and must also keep in mind that, upon the successful navigation of one challenge, another will be approaching just as quickly.

How do they (and how should you) cope?

If you watch slalom skiers, you'll notice that they seemingly take wide turns around each gate -- instead of taking a straight line from one gate to the next, which would require them to make an abrupt change of direction at each gate, they swoop in from wide of the gate, building speed through the turn toward the next flag. The rationale behind this strategy is that, by employing it, skiers can use the position of the next gate to set up the previous turn, always thinking further downhill and being prepared far in advance to avoid having to make last-second, ice-crunching, turn-on-a-dime turns that kill a skier's speed and waste valuable time. If the skier uses the downhill gates to set up his movements uphill, he can take as direct and efficient a line as possible, and maximizes his chances at success.

The GMAT affords you the same opportunity -- you've already noted that each question contains within itself five answer choices, but you may not have thought about using those "downhill" answer choices to set up your work.

Consider:

• If multiple answer choices include the square root of 3, there's a good chance you're going to have to use a 30-60-90 or equilateral triangle, as those triangles lend themselves naturally to sides with the square root of 3.



• If answer choices, similarly, include the square root of 2, you'll probably want to look for an iscosceles right triangle (45-45-90), for which the hypotenuse is going to have a side the length of the other side multiplied by the square root of 2.



• Other answer choices can guide you in the right direction, as well - look for clues such as denominators (do you need to end up with something divided by 3?), exponential terms (do you need to factor to get everything in terms of 2 to a power?), etc. If you let the answer choices be your guide, you'll often find that they provide you a template of what your mathematical goals should be.

As an example, consider the question:

What is 3⁸ + 3⁷ - 3⁶ - 3⁵?

(A) (3⁵)(2⁴)

(B) (3⁵)(2⁶)

(C) (3⁶)(2⁵)

(D) 6⁵

(E) None of the Above

The initial statement may not lend itself at first to any type of manipulation that would make it any clearer, but if you look at the answer choices, you’ll realize that your job is to try to convert the given statement to the multiplication of two exponential terms. Knowing that you’ll need to multiply an exponent of 3 by something else, you can determine that your first move is to factor out 3⁵, giving you:

3⁵(3³ + 3² – 3 – 1)

Looking again at the answer choices, it appears you’ll need to somehow find a base of two with an exponent, so it makes sense to simplify the parenthetical term to see if you can find an exponent of 2:

3⁵(27 + 9 – 3 – 1) = 3⁵(32) = 3⁵(2⁵)

Now, one last time, you’ll want to look at the answer choices. We’re close to A, B, and C, but each is one factor off. Answer choice D, 65, may look a little unlike what we have, but when you have the choice between an answer and “none of the above”, you’ll at least want to do your best to make your answer look like one of the tests. With 65, or something close to it, as our goal, we can play with our expression to see if we can restate it in that form. Doing so, we find that it gives us:

(3*2)⁵ = 6⁵

By using the answer choices as a guide, we took the initial statement and manipulated it until it looked like what we needed, employing that slalom strategy of looking downhill to set up our moves from the top.

To be successful on the GMAT, think like a slalom skier and see if the answer choices, like downhill gates, can set up your work for you as you seek efficiency. It's all downhill from there!

Author's Note: In honor of the 2010 Winter Olympics, Veritas Prep is offering 15% off all of its GMAT prep courses to students who enroll before the end of the Closing Ceremonies on Sunday. Use the offer code JULEZRULEZ2010 on any Veritas Prep course to qualify for the discount. (Veritas Prep congratulates fellow Californian Julia Mancuso on two silver medals to add to her gold from 2006!)