Data Sufficiency problems make up about two-fifths of the quantitative questions on the GMAT. They are not direct questions which ask to give the answer to the question. They ask to determine whether or not you can answer the question with the information given.
Data sufficiency questions don’t actually require you to solve the problem. Instead, you have to evaluate two statements and determine which of those statements provides sufficient information for you to answer the question.
A problem and two statements (1) and (2) are given in the question. All Data Sufficiency questions have following five choices:
It’s possible that just one of the statements gives enough data to answer the question, that the two statements taken together solve the problem, that both statements alone provide sufficient data, or that neither statement solves the problem, even with the information provided by the other one.
Take a methodical approach to answer data-sufficiency questions, and follow this series of steps:
In problem solving questions, the focus is to find the answers. However, in data sufficiency this is not the case. The focus here is whether you can find the answer or not? You only need to determine whether sufficient information is given to solve it.
You can memorize the answer choices. Though through practice this will be automatic process. There are five answer choices which are always same.
In Data Sufficiency, you have to first consider each statement separately. Only if both the statements alone are not sufficient, you should consider the sufficiency of the information in the combined statements.