### Data-Sufficiency

The Quantitative-Ability Section of GMAT consists of two types: Data-Sufficiency and Problem-Solving.

In the Quantitative-Ability Section of GMAT, you have to answer 37 questions in 75 minutes.

15 questions will be of this type and 22 questions will be of Problem-Solving type.

Questions of each of these types are not grouped separately, but are intermixed with questions of the other type.

Data-Sufficiency questions are unique to GMAT, and look particularly strange to few students who have never come across similar questions in any of their class tests or examinations.

The conventional questions in Mathematics give you a set of data and a problem, and ask you to work out the answer to the problem applying certain mathematical formulas to the given data.

In other words, the conventional problems ask you to solve the problems and arrive at the answers.

But in Data-Sufficiency questions, you are not asked to solve the problems. On the other hand, you are asked to merely determine whether it is possible for you to solve the problem using the given data and applying well-known formulae.

Here, you could find ten sample questions of Data-Sufficiency type. The questions in GMAT are of multiple choice types.

These questions do not expect you to perform complicated arithmetic calculations for arriving at the answer. On the contrary, they test your understanding of the fundamental and subtle principles of arithmetic, algebra and geometry.

These sample questions have been taken from the old GMAT question papers.

Answer each question yourself before reading the analysis that follows each question.

The following are the common instructions applicable to Data- Sufficiency Questions.

The following problem consists of a question and two statements labeled (1) and (2) in which certain data are given. You have to decide whether the data given in the statements are sufficient for answering the question. Using the data given in the statements plus your knowledge of mathematics and everyday facts (such as the number of days in July and the meaning of counterclockwise), you must choose the answer to the questions as A, B, C, D or E as follows.

A: If Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.

B: If Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.

C: If BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.

D: If EACH statement ALONE is sufficient.

E: If Statements (1) and (2) TOGETHER are NOT sufficient.

Read the instructions carefully and become familiar with these instructions.

Procedure for answering a Data Sufficiency Question

STEP - 1

Study the question carefully and understand what is asked. In particular, determine the type of question. Does it asks for a specific value as an answer, or is it a YES or NO type question.

STEP - 2

Examine the sufficiency of Statement (1).

There are two possibilities now.

Either Statement (1) alone is sufficient or Statement (1) alone is not sufficient.

If Statement (1) alone is sufficient

If Statement (1) alone is sufficient, the answer can only be (a) or (D), which means that the choices (B), (C) and (E) stand eliminated straightaway.

In other words, (A, D) and (B, C and E) form distinct groups among the answer choices.

STEP - 3

Now examine Statement (2) alone, forgetting for a moment what is stated in the Statement (1).

If you find Statement (2) alone also is sufficient information by itself, you must choose (D) as the answer. And then go over to the next question.

If on the contrary, you find Statement (2) as insufficient, you must choose (A) as the answer, and go over to the next question.

If Statement (1) is not sufficient

If Statement (1) alone is not sufficient, you can eliminate (A) and (D), and the possible choices are (B), (C) and (E).

Examine the sufficiency of Statement (2).

There are two possibilities now.

Either Statement (2) alone is sufficient or Statement (2) alone is not sufficient.

If Statement (2) alone is found to be sufficient, choose (B) as the answer. And then go over to the next question.

If Statement (2) alone is also found to be insufficient, consider Statements (1) and (2) together and examine whether the information in both of them together can enable you to answer the question.

If they can, choose (C ) as the answer.

If not then choose (E) as the answer and then go over to the next question.