GMAT Quantitative Tips: Preparing for data sufficiency questions

In your GMAT test preparation plan, the GMAT quantitative section would comprise of problem solving and data sufficiency questions. The data sufficiency questions tend to differ from the problem solving ones as you are not required to calculate the answer. There’s more to it than just your quantitative expertise. Rather it would test your ability to assess the data and apply your analytical skills to decide whether the data given is enough to solve a given problem.

There would be a question followed by statement 1 and statement 2. These statements would provide data related to the question. The answer choices would be based on these two statements. You would need to decide whether either of the statements, both or none would be sufficient to answer the given question.

Data sufficiency would comprise one-third of the quantitative section. The questions would range from problems based on algebra, geometrical concepts or basic arithmetic.

Consider the following example:

A few tips and strategies can help save time during the GMAT test.

Firstly it would be recommended that you memorise the five answer choices (A) to (E) and their order as this pattern would remain the same for each data sufficiency question.

Next you could employ elimination strategy wherein you strike out the wrong options.

• We would examine statement 1 independent of statement 2. By substituting various values or considering various scenarios, if you feel that statement 1 by itself is not sufficient, you would be able to eliminate options A and D.

• On similar grounds, if you check the data provided in statement B and feel that the data by itself is not enough to arrive at the answer then you would be able to strike out options B and D.

• On the other hand, if any one statement alone provides sufficient data, we would be in a position to eliminate options A and E.

It would be easier to understand the elimination method by applying it in the above example.

The example would require you to calculate the gross profit for the two items: armchair and coffee table. This objective would be borne in mind before we move ahead to check the relevance of the data statements.

Statement 1 gives information related to the purchase price but no details of the selling price, so we would not be in a position to calculate the profit. So we would deduce that statement 1 by itself is not sufficient. So we would rule out options A and D.

Statement 2 gives data about the relative selling price but there’s no mention about the purchase price, so this statement alone would not sufficient to arrive at the answer. Now option B too is ruled out. So we would be left with options C or E.

Now we would test if option C holds good. Though the relative purchase and selling prices are given, we do not have any data how to arrive at the actual figures. For example, as per statement 1, the purchase price of the armchair would be $110 if the coffee table was for $100 or it would be $220 if the coffee table was purchased at $200 and so on. The same condition would hold true for the data regarding the selling price. So we would infer that some additional data would be required to get an answer and hence option E would be the right answer.

In the above problem, we did not enter into complicated equations or number crunching hassles. We just applied logical reasoning along with mathematical concepts and a systematic approach in order to arrive at the answer. This would be the basic requirement of this section and should be remembered in order to speed up and give it your best during your GMAT test. As in any other section of the GMAT, practising a variety of questions on various topics will give you an ides of the type of questions asked.

Reference: Example sourced from our GMAT partner – Knewton.com