Use only the information given in the questions. The GMAT CAT seeks to measure your ability to distinguish facts from careless assumptions. Do not rely on a visual assessment of a diagram accompanying a geometry question to determine angle sizes, parallel lines, etc. In addition, do not carry any information over from one question to the next. Each question in the data sufficiency section of the GMAT stands on its own. You can count on seeing at least a few questions where a wrong answer choice tries 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 to solve math problems.
Use process of elimination. This GMAT section lends itself perfectly to using the process of elimination. If time becomes an issue, you can always look at the 2 statements in either order. Remember, the order you analyze the two statements in doesn’t matter, so long as you begin by looking at them individually. If you find statement 1 confusing, you can save time by skipping to statement 2 and seeing whether it can 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 the correct answer choice is either D or E. A favorite ploy of GMAT testers is to mix ratios and percentages. Here is an example where Statement 2 simply states backwards the exact same information provided by Statement 1.
1. x is 50% of y
2. the ratio of y:x is 2:1
Make real-world assumptions where necessary. You must assume that, in certain abstract questions such as “What is the value of x?”, that x might be a fraction and/or a negative number.
Practice, practice, practice. The more time you spend practicing data sufficiency questions, the better able you will be to internalize the tips and strategies given above. You will also become very comfortable with the type of questions from this portion of the test, and will quickly realize if there are any math areas, such as geometry or algebra where you need to brush up your skills. When it comes time to sit for the GMAT, you will want to know key math formulas and data relationships off the top of your head.
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