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Digging For Clues In Answer Choices on the GMAT

Submitted By Scott Shrum, Veritas Prep Director of Admissions

While many people view their GMAT study process as a trip down memory lane, reviewing algebra and geometry formulas from their junior high and high school days, it is important to remember that the G.M. in GMAT stands for “Graduate Management.”  Although most of the skills tested on the GMAT come from your teenage years, many of the thought processes that are rewarded come from your more recent – and stand to predict your future – business experience.

One extremely important set of those skills relates to leveraging assets – picking up on clues embedded within problems and leaning on those clues to help you achieve objectives.  And a place where you can improve upon that ability is the answer choices beneath Problem Solving problems.

By this point in your academic career you should know that you can “backsolve” problems by plugging in answer choices to the problem to see if they fit.  But a newer skill that commonly leads to success on the GMAT is looking at the answer choices to get an idea of what the correct answer should look like.  While many answer choices cannot be easily plugged in or eliminated through process-of-elimination, they can often help you determine your first step toward solving the problem. Consider the example:

What is (100,016)(99,984)?

(A)   1010 – 26
(B)   1010 – 27
(C)   1010 – 28
(D)   1010 – 29
(E)    (1010)(26)

While your first move might be to scramble for a calculator (which isn’t allowed on the test), you should notice a clue in the answer choices – all five answer choices involve 10 to the 10th power and 2 to an exponent.  Your goal is set for you – you have to find a way to take what you are given and create 1010 out of it.  What are your tools to do so?  Well, look at the first four answer choices, which all involve two exponents subtracted – that looks a lot like the “Difference of Squares” rule:  x2 – y2 = (x + y)(x – y).  Given that, you can rephrase the question as:

What is (105 + 16)(105 – 16)?

And since you know you need two to an exponent, you can rephrase the 16s as 24.  Now you have:

What is (105 + 24)(105 – 24)?

And that, given your knowledge of Difference of Squares, will look exactly like answer choice C.

More important than this example, however, is what you can learn from it.  Especially when answer choices involve large numbers and/or algebra, they are often extremely useful as clues to help you determine how to approach the math.  Sometimes your goal is to make the question look like the answers, and the clues embedded within the answer choices are essential parts of getting to work on that goal.  The GMAT rewards you for leveraging assets, so recognize that the answer choices are often assets in differing ways:

  • Numbers that you can plug back into the problem
  • Answers that you can eliminate via process of elimination
  • Clues as to what your “finished” math should look like (as in the example above)
  • Clues as to what type of number the right answer needs to be (Odd? Even? Negative?)
  • Far enough apart that you can estimate using easier values (for example, if you’re between answer choices like 279 and 319, try 300 and see if you need a higher or lower number than that)

The GMAT isn’t multiple-choice by accident – sure, it is easier to score, but it also sets up for questions that reward those who can leverage unseen assets.  Be sure to recognize those assets and put them to work.

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