When working on Distance-Rate-Time questions, you will inevitably use one of the following three formulas.
1. Distance = (Rate)(Time)
2. Rate = Distance/Time
3. Time = Distance/Rate
Did you know that there’s a quick and easy shortcut for recalling all three formulas?
The shortcut is similar to some of the shortcuts you learned in highschool science. It looks like this: D/RT (aka, the “DiRT” shortcut). As you may have guessed, D = distance, R = rate, and T = time.
Can you see all three formulas hiding in the simple fraction D/RT?
Here’s how it works. Let’s say, you need to recall the formula for finding the time it takes to complete a certain trip. Simply take the fraction D/RT and remove the T (for time). This leaves you with D/R. In other words, Time = Distance/Rate.
Similarly, if you need to recall the formula for finding the rate (speed), simply take the fraction D/RT and remove the R (for rate). This leaves you with D/T. In other words, Rate = Distance/Time.
Finally, if you need to recall the formula for finding the distance, take the fraction D/RT and remove the D (for distance). This leaves you with RT. In other words, Distance = (Rate)(Time).
So, instead of memorizing 3 formulas, just remember DiRT, which stands for D/RT.