GMAT Tip of the Week: The Data Sufficiency Reward System

GMAT Tip of the WeekIf you’ve studied for the GMAT for a while, you likely have a decent understanding of the answer choices:

(A) Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient to answer the question asked;
(B) Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient to answer the question asked;
(C) BOTH statements (1) and (2) TOGETHER are sufficient to answer the question asked, but NEITHER statement ALONE is sufficient;
(D) EACH statement ALONE is sufficient to answer the question asked;
(E) Statements (1) and (2) TOGETHER are NOT sufficient to answer the question asked, and additional data are needed

And you probably have a device to help you both remember these answer choices and use process of elimination. Some like “AD/BCE” (make your decision on statement 1 and cross out one side), others like “1-2-TEN” (1 alone, 2 alone, together, either, neither). But, ultimately, remembering the answer choices (which are always attached to the question on test day anyway) and understanding how to use process of elimination is just the “price of entry” for actually solving these problems correctly. For true Data Sufficiency mastery and a competitive advantage, you should think of the answer choices this way:

___D___
A_____B
___C___
___E___

Why?

As an added bonus it’s helpful for process of elimination (like the other tools) but as a strategic thought process it can be instrumental in using your time wisely and avoiding trap answers. Because what these answers really mean is:

___D___ — Each statement alone is sufficient
A_____B — One statement alone is sufficient; the other is not
___C___ — Both together are sufficient, but neither alone is sufficient
___E___ — The statements are not sufficient, even together

And since most Data Sufficiency questions are created with one of these constructs:

*One answer seems fairly obvious but it’s a trap
*One statement is clearly sufficient; the other is a little tricky
*One statement is clearly insufficient, but gives you a clue as to something you need to consider on the other

The above chart tells you how to better assess the answer given the answer that looks most promising. Consider a question like:

Set J consists of terms {2, 7, 12, 17, a}. Is a > 7?

(1) a is the median of set J
(2) Set J does not have a mode

For most, statement 1 looks very sufficient, as if a is the “middle number” then it would go between 7 and 12 on the list {2, 7, a, 12, 17}. That would mean that on this chart, you’re at A, as statement 2 is pretty worthless on its own:

___D___
A_____B
___C___
___E___

You can very confidently eliminate B and probably E, too, but if you’re sitting on a “probable A,” you’ll want to consider one level above and one level below your answer on the chart. Why? Because if the answer is, indeed, trickier than your first-30-seconds-assessment, the options are that either:

*The statement you thought was sufficient was close, but there’s a little hiccup (you thought A, but it’s C)
*The statement you thought was not sufficient was actually really cleverly sufficient had you just worked a little harder to reveal it (you thought A, but it’s D)

This is what Veritas Prep’s Data Sufficiency book calls “The Reward System” – many questions are created to reward those examinees who dig deeper on an “obvious” answer via critical thinking, and to “punish” those who leap to judgement and fall for the sucker choice. If A is the sucker choice, the answer is almost always D or C, so you know what you have to do…check to make sure that statement 2 is not sufficient, and then check (often using statement 2) to make sure that you haven’t overlooked a unique situation that would show that statement 1 is actually not sufficient. And here, further review shows this:

If a = 7, a is still the median of the set, but 7 is NOT greater than 7, so that answer would be “no” – there’s a way that a is not greater than 7, so we actually need statement 2. If there is no mode, then a can’t be 7 (that would be a duplicate number, making 7 the mode). So the answer is C, and the Reward System thinking can help make sure you streamline your thought process to help you identify that. If you picked A you’re not alone – many do. But if you picked A and then considered the chart:

___D___
A_____B
___C___
___E___

You should have spent that extra 30 seconds making sure that the answer wasn’t C or D, and that may have given you the opportunity to reap the rewards of thinking critically via the Data Sufficiency question structure.

So remember – merely knowing what the answer choices are is an elementary step in Data Sufficiency mastery; learning to use those to your advantage via the Reward System will help you avoid trap answers and stake your place among those being rewarded.

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By Brian Galvin

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