GMAT Tip of the Week: Be Aware, or Beware

GMAT PrepIf you drive a car, chances are you hate road cyclists.  What’s to like?  Awkward spandex clothing, goofy cleated-shoe walks at coffee shops, an odd sense of entitlement to the right-hand traffic lane…  But they say you can’t judge a man until you’ve walked (or ridden) a mile in his shoes, and if you did spend some time road cycling you’d understand this almost immediately: cyclists are the most alert and aware drivers you’ll ever meet, because they have to be.  And add a corollary to that, one that you would also learn as a cyclist: many drivers and pedestrians are dangerously unaware of their surroundings at virtually all times.

Cyclists simply must be aware of all potential obstacles on the road.  Tenuously perched on an inch-wide wheel, rapidly gliding along a road with two-ton pickup trucks to their left, parallel-parkers and door-openers to their right, narrowing road shoulders and street debris in front of them… each potential obstacle represents a brush with death or dismemberment and most of those obstacles come complete with either direct aversion to or an oblivious awareness of cyclists.  That will make you aware pretty quickly; if you’re not, it could all be over in a millisecond.

Quickly you learn to not just notice your surroundings but also to anticipate them.  When a driver changes lanes without a blinker, there’ s pretty good chance he’ll take another lane or make an unsignaled turn; drivers with vanity plates tend to make awful decisions; someone who pulls well into a corner before stopping to check oncoming traffic will almost never notice a pedestrian or cyclist on the shoulder; when brake lights turn off, that car has committed to pulling into traffic whether you’re coming or not.

Both cycling and driving are exercises in awareness. Think about it: you’ve ridden as a passenger in many cars in your day, and your level of fear isn’t directly correlated to how aggressive your driver is; the other, potentially more dominant factor is how aware she is.  You’re typically pretty comfortable when your driver exceeds the speed limit, but you’re not very comfortable when the driver doesn’t seem to notice the slowing traffic in front or when he mindlessly changes lanes.  The same goes for the drivers who frustrate you; it’s not as much the driver-in-a-hurry who passes you that ticks you off, but rather the slow driver in the passing lane or the car that tries to turn left from the right lane, slowing down all lanes in your direction.  These drivers simply lack awareness of their surroundings.  Awareness is the key!

Awareness is everything on the GMAT, too.  Just like some drivers “get it” (and we thank you) that they should leave space when approaching a merge, or that they should move to the right when traffic builds up behind them, some GMAT examinees just “get it” that intensive calculations are better solved by number properties and that technical reading comprehension passages should tend you toward looking at structural clues.  Success on the GMAT often comes down to those traits that also make for good drivers – awareness and anticipation.  Much as a good driver sees a situation and can predict what will happen next, a good test-taker will quickly note the wording or conceptual makeup of a question and predict what is likely to be important.  Consider the Data Sufficiency question:

Is x > 5y?

1) x/y > 5

2) y^2 < 5y

When a Data Sufficiency question includes an inequality, one of your first thoughts should be to anticipate the main unique concept about inequalities (versus equations): When multiplying or dividing by a negative, you must switch the sign of the inequality.  Accordingly, you should immediately be thinking that the GMAT will try to sneak multiplication-by-a-negative by you.  Here, it seems oh-so-natural to just multiply both sides of statement 1 by y to get: x > 5y —> YES!.

But what if y were negative?  In that case, that multiplication would switch the sign to: x < 5y –> NO.  Accordingly, since we can get both YES  and NO, statement 1 is not sufficient. And with your GMAT awareness, you should be anticipating that the statement would require you to think of both a positive and a negative.  When inequalities are present, that’s the most likely way that the GMAT will attempt to trick you.

Statement 2 is interesting – without a value of x, it cannot be sufficient on its own…x could be a trillion, or x could be negative-one-trillion.  We simply don’t know.  So, again, you should be aware and anticipate…why would the test offer a statement that provides no insight as to the potential values of x when the answer to the question requires knowledge of x?  It must be asking you whether statement 2 clears up the ambiguity of statement 1 with regard to y.  Statement 1 was insufficient specifically because we didn’t know whether y was positive or negative.  Can statement 2 clear that up for us?  At this point, that’s the only potential use for statement 2…it’s no good on its own, so we’re left to decide whether it can couple with statement 1 to provide value.

With that in mind, statement 2 -  tough to manipulate algebraically given that it’s a quadratic inequality – is much easier to handle.  Does statement 2 allow for a negative value of y?  It does not – the left hand side must be positive (it cannot be 0 because y exists as a denominator in statement 1, and if it were y were negative, when squared as it is on the left, it’s going to become positive), and so the right hand side, which is greater, cannot be negative.  Therefore, if 5y cannot be negative, then y cannot be negative, and we’ve eliminated that possibility from statement 1.  With both statements together, we can safely multiply both sides of x/y > 5 by y to get: x > 5y, which ensures the answer YES.  Accordingly, the answer is C.

More importantly, the lesson is that on the GMAT, as with driving, the key is to be alert and aware, and to anticipate situations before they happen.  A good many of us go through our daily commute or our GMAT prep seldom looking anywhere  but straight ahead, with blinders on to the world around us.  While that may not cause inherent problems on its own, it leaves us vulnerable to greater challenges.  To become more aware on the GMAT, as you learn new concepts and see more problems ask yourself what kinds of  “danger” they may present, or which situations they lend themselves best to.  For example:

The word “nonnegative” allows for both a positive number and for zero, and zero is a tricky number.

When the word “factor” appears in a question stem, it’s quite likely that breaking numbers down into prime factors will give you a blueprint of what you need.

The most common calculations that would lead to answer choices that include the square root of 3 are those related to 30-60-90 and equilateral triangles.

The GMAT is a test that rewards awareness, and with its timed component the quicker you can anticipate a situation the more efficient you’ll be.  Train yourself to notice and anticipate common GMAT constructs and you’ll put yourself on a path toward success.  Oh, and be nice to cyclists on the road…they may seem like a nuisance on their bikes, but as fellow motorists they’re the safest you’ll ever encounter.

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One Response

  1. macjas says:

    This is a very insightful article Karishma. I’ve come across these question types before and while it is possible to find the roots of a quadratic inequality often times it may not be necessary. Essentially, GMAC disguises +ive/-ive type questions in the form of inequalities.

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