Introduction
GMAT problem solving questions are
designed more to test your understanding of underlying
mathematical concepts than to test your ability to
actually carry out quantitative procedures accurately.
Fortunately for many test takers, advanced quantitative
topics, such as trigonometry and calculus, are not tested
on the GMAT. To score well, you only need to be
familiar with basic arithmetic, geometry, and
algebra, as taught at the high school level. Any
decent GMAT prep book will cover these quantitative
concepts.
Problem Solving
Tips and Strategies
Read the questions carefully.
It is impossible
to overstate the importance of careful reading. The most
common pitfall GMAT test takers stumble into is
answering the question they thought they read, instead
of the one the test asked. There is a
big difference between a question asking "Which of
the following may be true?" and one asking "Which of
the following may not be true?" The test writers
deliberately include answer choices that correlate to common
misinterpretations of the questions.
Use your scrap paper for every question. No
matter how easy a question appears, you should utilize
your scrap paper. Seeing a calculation on paper will
help you avoid easy mistakes and the answer choices designed to exploit them.
Remember,
once you record your answer on the GMAT CAT, you can't
go back and change it. This aspect of the CAT makes
this tip even more effective.
Do not get bogged down with complicated or lengthy
calculations. We have looked at hundreds
of GMAT problem solving questions and found that they are deliberately
designed to make such calculations unnecessary. You
are overlooking a shortcut if you find yourself getting
bogged down in this way.
The "guesstimating" technique
is extremely effective on this exam. Most
of the time, the answer to a problemsolving
question is a value, and the values given in the answer choices
will not be very close to each other. As a result, you can save
time by 'guesstimating.' For example, if you know the
value you're looking for is about 30%, and the answer
choices are 4%, 13%, 29%, 47%, and 81%, you can safely
guess that the correct answer is 29%. Congratulations
– you just saved yourself a lot of time on this question, and
avoided getting caught up in a longer calculation that might
have resulted in a math error!
Learn how to work backwards. If
you are completely stuck on a question, you can always
try plugging in an answer choice and work backwards to see
if it makes sense. When you use
this technique, we suggest starting with the choice
giving the middle value. Even if the middle value does not answer the
question, it might tell you if you need to go higher
or lower. You will have
narrowed 5 choices down to 2.
Convert quantities freely. There
are often shortcuts available to you if you can
recognize
relationships between the numbers used in the problems.
Keep in mind, the GMAT test writers never haphazardly
select numbers for their questions. This technique is especially useful in narrowing down
likely answer choices when you feel the urge to pull out
a calculator. One easy conversion to remember
is that, at least for purposes of the GMAT, π = 22/7.
Use process of elimination as a last resort. The
GMAT writers have historically arranged answer
choices in ascending numerical value. Even if you are
unable to immediately hone in on the correct answer, chances are
that guesstimating, working backwards, or some other technique
will help you eliminate many wrong
choices.
Practice, practice, practice.
When you spend time practicing quantitative questions,
you internalize these tips and strategies. You will also
become very comfortable with the type of questions found
on this portion of the test, and will quickly realize
whether you need to brush up your skills in any math
areas, such as geometry or algebra. After all, when
it comes time to sit for the GMAT, you will want to be
able to recall certain information – the total number of degrees in the sides of a
triangle, the calculation for the area of a circle,
etc – off the top of your head.
ProblemSpecific
Tips and Techniques
There are several distinct types of
quantitative problems, each of which can be approached with specific tips and strategies:
Geometry Problems
Assume diagrams are drawn accurately unless
the question specifically states otherwise. Do
not, however, rely on your visual judgment to answer
these questions. The test writers never allow
their questions to be that easily answered. One common
mistake is to assume that 2 lines must form a right angle,
when this is not specifically indicated in the text. Do not
fall into this trap – it is one of the most common mistakes
made on the GMAT.
Spend at least 30 seconds reviewing the diagrams. Many
implicit facts and numbers can be found inside
these illustrations. Due to the computeradaptive nature
of today's GMAT, you will need to sketch out the diagrams
on your scrap paper to deduce the implicit facts from
the data explicitly given.
Graph Problems
Spend at least 30 seconds reviewing the graphs
and tables. Graph problems are not meant
to require hard math calculations. Instead, they are
designed to test your ability to interpret and use
information contained in graphs and tables. As
a result, you will be well served by closely studying the structure
and basic content of the graphs and tables. The
axis labels, legend key, and units of measurement
are more important to you in
understanding and answering the question than the actual
data presented.
Make sure you are familiar with bar, circle, and
line graphs. These are the 3 graph types
most commonly presented on the GMAT.
You can rely on visual estimates for bar
graphs and line charts. The test writers
will not use visual tricks to deceive you. In fact,
you will often
times have to trust a visual estimation to
determine the correct answer. Note:
Visual estimates will
not work with geometry questions.
"Weird" Problems
Identification is half the battle.
Train yourself
to recognize when you're dealing with a "weird" problem,
and deal with it accordingly. AdmissionsConsultants defines "weird" as
problems that simply test your reasoning skills,
not your quantitative skills. These questions are widely
considered the most intimidating on the entire exam.
An excellent example of this genre
of question is a problem that presents a function you never learned
in school. You will greatly improve your odds of answering it
correctly by calmly and methodically imitating the "logic" presented
in the question. If this fails, you can always work
backwards to solve the problem.
Word Problems
Build equations for word problems. When
dealing with a word question (such as what happens if trains
are traveling
at a certain speed), build an equation that will help
you understand
the question being asked and find the answer. Use obvious letter symbols such
a "A" for train A, "B" for Bob's
age, etc., to stand for the values you need to calculate.
Don't waste time looking for subtle meanings. You
can make reasonable assumptions with these questions.
The test writers are not trying to trick you in this
way.
Click here
to see our problem solving practice questions.
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