GMAT Problem Solving

Introduction

The problem solving questions of the GMAT test are designed more to test your understanding of the underlying mathematical concepts than to test your ability to actually carry out the quantitative procedures accurately.

Fortunately for many test takers, advanced quantitative areas such as trigonometry and calculus are not tested on the GMAT. To score well, you will only need to be knowledgeable of the basic arithmetic, geometry, and algebra that are 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. This is the most common pitfall that GMAT test takers make and it is hard for us to overstate this. There is a big difference between the questions “Which of the following may be true?” and “Which of the following may not be true?” The test writers deliberately include choices that correlate to common misinterpretations of their questions.

Use your scrap paper for every question. No matter how easy the question appears, you should utilize your scrap paper. Seeing the calculation on paper will help you avoid many of the easy mistakes and the corresponding answer choice designed to exploit that mistake. Also, 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 these GMAT questions and 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 is a value, the choices will not be very close to each other. As a result, if you can save time and closely guesstimate the answer to be 30% and the choices are 4%, 13%, 29%, 47%, and 81%, then you will know the answer must be 29%. Congratulations, you just saved a lot of time on this question and avoided a longer calculation that would have greatly increased the chances of committing a math error!

Learn how to work backwards. If you are completely stuck on a question, you can always try to plug in an answer and work backwards. If you do this, we suggest you start by plugging in the middle value. If this answer does not correctly answer the question, it may at least tell you if you need to plug in a smaller or larger value. In this case, you have narrowed your initial 5 choices down to 2.

Convert quantities freely. There are often shortcuts available to you if you see certain 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 most often used in questions where you get 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 the answer choices in ascending numerical value. Even if you are unable to hone in on the correct answer, chances are guesstimating, working backwards, or some other technique will help you at least eliminate many of the wrong choices.

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 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.

Problem-Specific Tips and Techniques

There are a few distinct types of problems that have their own specific tips and strategies:

Geometry Problems

Assume the 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 form a right angle when this is not specifically indicated. Do not make this assumption as 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 are often contained inside these figures. Due to the computer-adaptive 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 designed to include hard math calculations. Instead they are designed to test your ability to interpret and use information contained in the graphs and tables. As a result, you will be well suited to study the structures and basic contents of the graphs and tables. The axis labels, legend key, and units of measurement are more important 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 estimations for the bar graphs and line charts. The test writers will not use visual tricks for deception. You often times will have to trust the visual estimation to determine the correct answer. Note: this will not work for geometry questions however.

“Weird” Problems

Identification is half the battle. AdmissionsConsultants^SM defines “weird” as problems that simply test your reasoning skills and not your quantitative skills. These questions are widely considered the most intimidating on the entire exam.

An excellent example of this genre of questions is when a new function is presented that you never learned in school. When you come across this type of problem, 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.

Word Problems

Build equations for word problems. When dealing with a word question (such as trains traveling at a certain speed) build an equation that will help you get the answer. Use obvious letter symbols such a “A” for train A, “B” for Bob’s age, etc.

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.

Problem solving practice Questions