Introduction
The GMAT test writers use the data sufficiency questions
to test your ability to "reason quantitatively".
This stands in sharp contrast to the problem solving
section which is designed to test how well you manipulate
numbers. As a result, if you find yourself doing much
number crunching with the data sufficiency questions,
you are doing something wrong.
Math Concepts
You Should Know
The data sufficiency questions cover the math areas
that nearly every college-bound high school student
will know. In addition to basic arithmetic, you can
expect questions which will test your knowledge of
averages, fractions, decimals, algebra, factoring,
and basic geometry such as triangles, circles, and
areas and volumes of simple geometric shapes.
The Answer Choices
The GMAT's data sufficiency questions will all have
the exact same answer choices. Memorize these answer
choices before you take the exam. It will help you
better utilize your time in the quantitative section.
The answer choices are summarized below as you will
see them on the GMAT exam.
- Statement 1 alone is sufficient but statement 2
alone is not sufficient to answer the question asked.
- Statement 2 alone is sufficient but statement 1
alone is not sufficient to answer the question asked.
- Both statements 1 and 2 together are sufficient
to answer the question but neither statement is sufficient
alone.
- Each statement alone is sufficient to answer the
question.
- Statements 1 and 2 are not sufficient to answer
the question asked and additional data is needed
to answer the statements.
Use Process
of Elimination
If statement 1 is insufficient then choices A and
D can be immediately eliminated.
Similarly, if statement 2 is insufficient, then choices
B and D can be immediately eliminated.
If either statement 1 or 2 is sufficient on its own,
then choices C and E can be eliminated.
A Simple 4
Step Process for These Questions
It seems a common mistake many test takers commit
is to lack an exhaustive and analytical methodology
to analyzing these questions. A simple tendency to
overlook a step in the process below can make a big
difference in the final quantitative score you will
be reporting to your selected business schools.
1.) Study the questions carefully. The
questions generally ask one of 3 things: 1) a specific
value, 2) a range of numbers, or 3) a true/false value.
Make sure you know what the question is asking.
2.) Determine what information is needed to solve
the problem. This will obviously vary depending
on what type of question is asked. To determine the
area of a circle, you will need to know either the
circle's diameter, radius, or circumference.
3.) Look at each of the two statements independently
of each other. Follow the process of elimination
rules covered above when considering each statement
individually.
4.) If step 3 did not produce an answer, then combine
the two statements. If the two statements
combined can answer the question, then the answer
choice is C. Otherwise, E.
Data Sufficiency
Tips and Strategies
Use only the information given in the questions. The
GMAT CAT tries to measure your ability to distinguish
facts from careless assumptions. Do not rely
on a visual assessment of a geometry question to determine
angle sizes, parallel lines, etc. Finally, do not carry
any information from one question to the next. You
can count on seeing at least a few questions where
a wrong selection is presented just to capitalize on
this common fallacy.
Do not get bogged down with complicated or lengthy
calculations. As we stated before, these
questions are designed to test your ability to think
conceptually, not solve math problems.
Use process of elimination. This
GMAT section lends itself perfectly to process of
elimination.
If time becomes an issue, you can always look at the
2 statements in either order. Hence, if statement 1
is confusing, look at statement 2 to help you eliminate
incorrect answer choices.
Be on the lookout for statements that tell you
the same thing in different words. When
the 2 statements convey the same exact information,
you will know through process of elimination that
your choices are D or E. A favorite of the GMAT testers
is to use ratios and percentages. Here is an example
where Statement 2 simply states backwards the exact
same information provided by Statement 1.
- x is 50% of y
- the ratio of y:x is
2:1
Make real-world assumptions where necessary. The
test makers will not try to trick you in this way with
these questions. However, you must assume in certain
abstract questions such as "What is the value
of x?" that x can be a fraction
and/or a negative number.
Practice, practice, practice. If
you spend some time practicing these questions, you
will
be able to internalize these tips and strategies. You
will also become very comfortable with the questions
from this portion of the test and will quickly realize
if there are any math areas such as geometry or algebra
where you will need to brush up on your skills. When
it comes time to sit for the GMAT, you will want to
know the important data relationships for the various
math areas tested.
Click here to see our data sufficiency
practice questions.
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