Strategic Elimination and Pacing – Add Points to Your Quant Score

As a Kaplan instructor, one of my primary goals is to make students comfortable with a variety of methods and strategies that will help them on test day, and build up their confidence in their ability to apply these strategies. For example, take this problem:

Employee X is paid $19.50 an hour no matter how many hours he works per week. Employee Y is paid $18 an hour for the first 40 hours she works in a week and is paid 1.5 times the hourly rate for every additional hour she works. On a certain week, both employees worked the same number of hours and were paid the same amount. How many hours did each employee work that week?

(A) 32

(B) 36

(C) 40

(D) 42

(E) 48

This problem looks like it’ll take a lot of calculation to solve, but let’s think critically. If each employee worked a regular 40-hour week, could they be paid the same amount? No – until we get past the 40-hour mark, employee X will always out-earn employee Y. Employee Y thus has to work more than 40 hours and get some overtime pay to even things out. So without putting pencil to paper or using the calculator, we’ve eliminated 3 out of the 5 answer choices. Now, we can just test out either choice (D) or choice (E) – if the one that we choose to test out gives us the same weekly pay for both workers, then great! We’ve found the answer. And if it doesn’t, then (still) great! We know that the other choice must be correct.

Inevitably, whenever I teach this, at least one student says, “But I could just set up an equation and solve this algebraically – what’s the point of even trying to solve this way?” Here’s why: Pacing. In each quantitative section, you have to complete 20 questions in 35 minutes. Overall, that’s less than an average of 2 minutes per problem, and some problems will take far longer than the average to complete. And don’t forget: The better you get at the first quant section, the more difficult the second section becomes.

To save time for the really tough questions, you need to bank as much time as possible on any problem that can be solved by applying a strategy and critical thinking instead of doing a slew of calculations. And when you practice, you want to ask yourself not only “How can I find the correct answer?”, but also “How could I eliminate as many incorrect answers as possible if I saw this problem with 15 seconds left in the section?” If you do so consistently, you’ll put yourself miles ahead of the competition and add points to your GRE score on Test Day.