Anatomy of a Tough OG Graphing Question
Co-ordinate Geometry (often referred to as ‘graphing’) is a rare subject in the Quant section of the GMAT. On Test Day, you’ll likely see just 1 or 2 graphing questions in total, so that subject is not a big contributor to your overall score. While certain graphing questions can be remarkably easy to solve, others can be rather ‘layered’ and will require some time and effort on your part.
Thankfully, graphing questions always revolve around the same handful of ‘math rules’; if you know your graphing rules, then you should be able to deal with whatever variations the GMAT throws at you.
Consider the following graphing question (it appears in the OG13, GMAT2015 and GMAT2016 books):
OG13, GMAT2015 - Page 286, #129
GMAT2016 - Page 290, #144
How did you handle it? How did you organize your work? How long did it take to solve?
If you haven’t attempted it yet, and you’d like a few ‘hints’, then I’ve provided some notes (they appear below the link which shows how you can approach the prompt using the EMPOWERgmat tactic TEST IT).
1) When graphing lines, it often helps to rewrite any equations you’ve been given in slope-intercept format (Y = MX + B).
2) Once you have an equation, graphing individual points can (and often should) be done so that you can physically ‘see’ what the line looks like. Graphing an inequality just means that you have to consider additional points that are NOT on the line.
3) When TESTing VALUES and dealing with inequalities, it often helps to consider how ‘big’ or how ‘small’ your values can get.
You may have spent some significant time working on this question (and that’s okay during practice), but how much of that time was spent doing actual WORK and how much of that time was spent deciding what to do (and staring at the screen or your notes)?
Remember that GMAT Quant questions are almost always based on rules that you already know, but will sometimes be presented in a way that you’re not used to thinking about. Staring at the screen is never the answer – putting pen to pad, taking notes, working through ideas, etc. is part of what it takes to score at a high level. Learning to work efficiently is the other part. Thankfully, we can show you how to do both.
GMAT assassins aren’t born, they’re made,