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Data Sufficiency - Introduction

Introduction to Data Sufficiency 

Data sufficiency questions consist of questions and two statements. These statements contain data or information. Questions are based on any topic which we have already studied in quantitative aptitude viz , Numbers, Averages , Percentages, Mensuration, Algebra and reasoning topics like blood relations , puzzles etc.
Data sufficiency questions are not only difficult but confusing also. Data sufficiency questions require deeper knowledge in the subject area.Test takers generally get confuse with the given information.
In data sufficiency questions, we have to decide whether the data given in the statements labeled as 1 or 2 are sufficient to solve the given problem , There are 5 possible answer
Option A : If statement 1 itself is sufficient to answer the question, but statement 2 itself is not
Option B : If statement 2 itself is sufficient to answer the questions, but statement 1 itself is not
Option C : If statement 1 and 2 together are sufficient to answer the question, even though neither statement by itself is not sufficient
Option D : If either statement itself is sufficient to answer the question.
Option E : Statements (1) and (2) TOGETHER are NOT sufficient to answer the question asked, and additional data specific to the problem are needed.

In data sufficiency questions, to answer the questions, students don’t actually have to calculate the values or answers. Students only have to determine whether the data given in the statements are sufficient to find the answer for the given question.

There are different kinds of data sufficiency questions:
1.    For exams like IIM-CAT , there are only four options
2.    For exams like GMAT  , options are five
3.    Sometimes above given options may be jumbled
4.    One or two options may be new type , while remaining are same as above options
5.    There may be three or 4 statements follow a questions

How to solve Data Sufficiency Questions:
Tips to solve the questions based on data sufficiency:
1.    The most important is understanding the options. In CAT exams, students may have data sufficiency questions with 4 options and in GMAT options are fixed .In some other competitive exams options in data sufficiency question vary.
2.    Read the questions carefully. Means , the parent questions that is asked
3.    First check the  statement 1 .Look at the statement 1 and the information given in that. See whether information given in statement 1 is sufficient to answer the question. When you see statement 1, ignore the information given in statement 2
4.    Check the statement 2. Look at the information given in the statement 2 . Most important that when information given in statement 2 is considered, just forget the information given in statement 1. See whether the information given in statement 2 only is sufficient to answer the question.
5.    When the statement 1 and 2 are individually not enough to answer the question, use the information given in the both the statements.


1. Data Sufficiency Problems On Numbers -1 

2. Number System- Data Sufficiency Problems

3.Data Sufficiency Questions on Percentages 

4. Data Sufficiency Questions on Problems on Ages

4.Data Sufficiency Questions on Clocks and     Calendars