Hi GMATters,

Here's a copy of my newest guide. It got a little bit out of control, but that's for your benefit.

I've tried to include all the common variants of GMAT rates here and cut through the nonsense approaches that I tend to see in GMAT literature.

Have a read and let me know what you think--it's fresh so if any issues with images, calculations, etc. please feel free to let me know!

https://yourgmatcoach.withcoach.com/free-52-page-pdf-guide-how-to-tackle-any-gmat-rates-question
Rowan

Here's a sample:

Why Focus on Rates?
Getting good at Rates questions is like a superpower on the GMAT. Rates questions come up a lot, and few people are actually any good at them, so--like factoring questions--they’re worth a bit more than their actual difficulty might suggest.

Add into the mix the fact that most books give about twelve different formulations of the standard Rates formula and expect you identify which formulation goes with this particular question...

Geez, I’m out of breath even saying that.

Let’s clear up some of the crap and go back to basics.

The Standard Formula (d = r * t )
The good thing about Rates questions is that they’re all, ultimately, based on a statement as simple as this:

If you drive a car at 60 miles per hour for one hour, you’ve traveled 60 miles.

If that wasn’t simple or you’re from “a civilised part of the world,” then forgive me for insulting your delicate sensibilities. Instead, you can phrase it this way:

If you drive a car at 100 kilometers per hour for one hour, you’ve traveled 100 kilometers.

In short, “distance equals rate times time.” Want the equation?

Distance = rate x time

Or

d=r*t

Keep that in the back of your mind, because we’re going to come back to that in every section that we cover for, well, the frickin entirety of this guide.

Bear with the Simple Physicist

The real problem with Rates in most GMAT texts is the fact that books tend to overcomplicate the problems.

They offer about twelve different variants of d = r * t that apply in different situations.

On top of memorizing those different variants, it’s often completely unclear which situation requires which equation!

The GMAT capitalizes on this, of course, and presents situations that will not easily fit into any of the twelve prescribed equations!

The trick to this, of course, is to ignore those equations and just make life simple for yourself. As a person who studied Physics, I am inherently lazy about math and I prefer the method that just gets things done.

In the words of the great philosopher Montell Jordan, this is how we do it.

How to Simplify Rate Questions

For someone like me, who can barely remember his own phone number, equations don’t make a lot of sense. That’s why I love d = r * t . It’s a priori (self-evident). (Before you get squirrly--yes, that may not be true on the deepest philosophical level--but if we set our logical goalposts within reason and accept things such as, you know, time and gravity, to exist then we’ll be fine.)

Grab the full guide here!

https://yourgmatcoach.withcoach.com/free-52-page-pdf-guide-how-to-tackle-any-gmat-rates-question