The GMAT is a difficult test. But you knew that — that’s probably why you’re reading this, because you’re looking for insight. One important insight is to accept and recognize that it’s a hard test and that you have to earn most correct answers, as there is little value to business schools in a GMAT question that does not separate the elite candidates from the simply-above-average applicants.
How can you become part of that elite group? One way is to not just accept that the GMAT is hard, but to use that fact to your advantage. Knowing that the GMAT is a hard test, you can train your gut to recognize when an answer choice just seems too easy, and accordingly use your problem solving skills to root out the reason why.
Consider the Data Sufficiency question:
Given that x and y do not equal 0, what is the value of x/y?
(1) 9y/x = 2/x – 4
(2) 12x/y + 27 = 12/2y
Even a quick glance at the statements could alert you to the fact that neither alone looks to be sufficient. The -4 term in statement 1 and the +27 term in statement 2 won’t allow themselves to be expressed in terms of x or y – you’re stuck with an extra numerical value that won’t break into that x/y ratio.
Should you even break them down, you’ll note that, for statement 1:
9y = 2 – 4x (multiply both sides by x)
For statement 2:
12x + 27y = 6
Again, you should note that you won’t be able to get to an x/y term because of the presence of those numerical terms (now 6 and 2).
So if A and B are eliminated as answer choices, C looks pretty obvious, right? 2 equations and 2 variables, which you could see from the beginning should allow you to solve for both. But this is a hard test! Cs don’t come easy, so you should be a little leery of that 2 statements, 2 equations, 2 variables setup.
One incredibly clever trick that the GMAT has up its sleeve is to provide you with two statements that are mathematically identical, so when you do feel that twinge of “too easy” anxiety, that’s a great spot to double check. Express each statement in the same way and you’ll find that they are:
9y = 2 – 4x
27y = 6 – 12x
Look familiar? You know that the GMAT has a preference for factoring, so it makes sense to factor out common terms in any equations or fractions. Each term in statement 2 is divisible by 3, so divide out the 3s to find:
9y = 6 – 12x
In the end, you only have one unique equation, and the correct answer is E.
Axioms like “if it seems to good to be true, it probably is” and “there’s no such thing as a free lunch” pervade the business world for good reason – good managers will recognize situations that look promising on the surface but have significant flaws underneath. Demonstrate to business schools that you have exactly that instinct – when a Data Sufficiency question seems to offer you an easy answer, investigate further!