Quantitative Comparison Tutorial Overview Quantitative comparisons are featured prominently on some standardized exams and do not appear at all on others. In this tutorial, we'll give you tips that apply to the most common forms of quantitative comparison questions. Keep in mind that we are addressing only the most frequently seen format for quantitative comparison questions. Other formats exists, but we won't go into detail on them because once you understand these basic rules, you should be able to adapt them to whatever form the questions take. Basic Rules When you are comparing the values in two columns, there are some simple rules to keep in mind. Let's take the following example: Column A 15 + x Column B 20x You're asked to select one of four possible answers: A if the quantity in Column A is greater; B if the quantity in Column B is greater; C if the two quantities are equal; D if the relationship cannot be determined. Here are some the rules of thumb: 1) If the value in Column A is greater, you can eliminate answers B and C. The answer will never be that Column B is greater or that the two quantities are equal. 2) If the value in Column B is greater, you can eliminate answers A and C. Again, the answer will never be that Column A is greater or that the two quantities are equal. 3) If the two columns are equal, you can eliminate A and B. This technique will help you get rid of wrong answers without wasting too much time on them. Now take some numbers and plug them into the example above. What if x is equal to 1. Column A 16 Column B 20 What if x is equal to 0. Column A 15 Column B 20 What if x is equal to -1. Column A 14 Column B -20 It becomes clear by this point the answer is D. From the information given, we simply cannot determine the relationship. As you can see, by picking simple numbers for x, we can quickly come to this conclusion. Another approach for quantitative comparison questions is to treat the question as an equation. For example: (Column A < Column B) or (Column A = Column B) or (Column A > Column B) Now that you have it in this form, you can easily begin to manipulated it by adding the same quantity to each side or subtracting the same quantity from each side. Depending on the values of Column A and Column B, this may help to simplify the equation and make the answer more obvious. You can also multiply each side by the same quantity or divide each side by the same quantity. Whatever you think will help to clarify the mathematical relationship. Keep in mind that in the case of inequalities, you should only do this if the quantity you are multiplying or dividing by is positive. Otherwise, you'll wind up changing the nature of the equation. Equality Test Another trick for solving a quantitative comparison, where one column contains a variable and the other contains a number, is to ask yourself the question, can the quantities in the two columns ever be equal? If the answer is yes, you can quickly eliminate possibilities A and B. Once you've established this, ask yourself if the quantities in the two columns must be equal. If the answer to this is yes, then you know that C is the correct answer, otherwise, the answer is D. Compare First When approaching a quantitative comparison, don't grab your calculator and start trying to solve the equations in each column. First, try to compare the two columns without doing any calculations. Often you'll find it's easy to determine the relationship between the columns without spending time on complex arithmetic. That said, if the arithmetic is easy, it doesn't hurt to do it. You just don't want to get bogged down in arithmetic calculations if the relationship between the columns can be determined by a simple comparison. Fixed Numbers When performing the quantitative comparison, if the quantities in both columns are fixed numbers, then D can never be the answer. In other words, there will never be a case where you cannot determine the answer if both columns contain only fixed numbers.