On Rates, Speeds, and Out of Date Test Prep Materials

Often, when I begin working with a new tutoring student who has been studying for a while, he or she will sigh in our first meeting: "It's those awful rate and speed problems that really get me down." I often reply, as I did in my tweet today:

"Oh, something like, 'If A heads towards B at x mph, and B heads towards A at y mph, when will they meet?' "

The student usually says, "exactly!"

And I say: "The answer is: 'you probably don't care.' "

Let me explain.

The GMAT has changed over the years. The content that you see in the Official Guide is not always reflective of what is currently on the exam. Many of the questions in official guide 12 were also in official guide 11 and official guide 10 and official guide 9...... How reflective do you think that question really is of what the test really is like?

Further, many test prep companies write their practice problems by mimicking particular problems from the Official Guide. Then, those companies will often write more problems by mimicking the problems they already wrote! Also, if a particular question is retired from the Official Guide, do you really think that the test prep company will dig through their materials and find the questions that they based off of that particular question, and retire those? No way! They paid someone to write that question and they're not going to waste that resource. So you go to a class at a major test prep company, and get taught by someone who might never have taken the real GMAT (some test prep companies allow their teachers to score qualify on practice tests instead of real ones), and you work your way diligently through practice problems that are clones of clones of clones of questions that were out of date four or five years ago. Your teacher, who might never have seen a real GMAT, might have score qualified 4 or 5 years ago, or might just be forced to spout company rhetoric against his/her own better judgment, will probably not set you straight.

One of the most obvious examples of this is the preponderance of awful rate and speed questions in GMAT practice problems. Could you potentially see one actual real rate/speed word problems, with cards driving around and crashing into each other or whatever? Yeah, maybe one. Maybe two on a freakish day. But if you took the GMAT four or five times, I bet that you'd see just one or two actual rate and speed questions on all the tests put together.

So, if you can do rate and speed questions, great. You might get one, and it's always worth it to tag every base. But if rate and speed questions are causing you untold misery, you can heave a sigh of relief.... and go open a number properties book and start studying that, because that is what you'll be tested on.

Further, if you are having rate and speed issues, think about why you're having rate and speed issues. Are you having trouble with word problems in general? Are you having trouble with algebra? Do you have trouble visualizing things, or organizing lots of details? Those are things to be concerned about. Take a step back and look at the root causes, not the surface expression of the issues.

The only reason I can see to learn how to do them is that they're not that bad! I'll write a post some time on how to do them. Until then, I was serious about that number properties thing. Get to it!