Data Sufficiency– A Nightmare?

The GMAT quantitative Section consists of 37 questions of primarily two types – problem solving and data sufficiency. People with little exposure to the GMAT or those whose preparation has not been well-structured feel Data sufficiency is the trickiest part of the quantitative section.

In reality data sufficiency questions are not as hard as they are believed to be and with some techniques one can easily master them. Some important techniques have been enumerated below.

• Understand the choices

Answer choices are the same in all data sufficiency questions. So the first and the most important thing is to familiarize yourself with the answer choices.

• Read and simplify

After reading the question simplify it as much as possible and check what is asked in the question.

• Understand what you need

Once you rephrase it, the second step is to check what you need to answer in that question.

• Look for what you need.

Last step is to check for the values you are looking for in Statement 1 and Statement 2 alone; if neither of the statement is sufficient alone then check both statements together.

Example:

Is k + k <k ?

(1) k²>k³

(2) k³>k²

Question is”Is k+k <k?”

Simplification

k+k<k

Subtract k from both sides of the inequality

k+k-k<k-k

After simplification, the question is “Is k<0?”

In order to solve this question one needs information about k. Now look for k in each statement one by one.

Statement 1 is k²>k³

Be careful here as you may multiply or divide both sides of an inequality by the same positive number, and the sense will not change but if you are multiplying or dividing same negative number then the sense of inequality will change. And in this statement we can divide both sides by k² because the square of a number, whether it is positive or negative, always give you positive result.

k²/k²>k³/k²

1>k

Statement 1 is telling us that k is less than 1 so it can be any number less than 1. So it is insufficient.

k³>k²

Again you can divide the inequality by k² on both sides.

k³/k²>k²/k²

k>1

Statement 2 is telling us that k is greater than 1 so K is not a negative number. So answer for the question “Is k<0? Is no.

Answer is B means Statement 2 alone is sufficient to answer the question but Statement 1 alone is not.

Summary: All Data sufficiency questions require a 3 -step approach

• Read and simplify the question.
• Check what one needs to answer the question.
• Look for what one needs in the statements.