In this series we return to classic movies (and TV shows!) to learn fundamental strategies for GMAT Success.
My friends from the television show The Big Bang Theory are fond of super heroes. Okay Sheldon and Leonard are not really my friends (unfortunately) but they are certainly fond of super heroes. They love Superman and Batman and the entire Justice League.
What they fail to understand is that they are super heroes themselves…with super powers that translate extremely well to the GMAT. Their biggest super power? Making equations of course!!!
You are a Super Hero, too.
You don’t think that making equations is a super power…did you not hear that music while Sheldon and (Raj) Koothrappali were working on that equation? That was super hero music for sure!
While making equations may not be as cool as flying; on the GMAT the ability to see an equation where others may not is indeed a super power. A super power that you may already possess.
All that you need to do in order to create an equation is to set two things equal. Moreover, if any two things are equal to a third then they can be set equal to each other and you have another equation!
This is something that is easiest to illustrate in Geometry. In fact, this is the essence of geometry. If you know that the area of a triangle is Base * Height / 2, and you also know that the area of the triangle is 30, then you drop the thing that they have in common (in this case the area) and create the equation from the other two pieces: Base * Height / 2 = 30, or Base * Height = 60.
You are so used to having this super power at your disposal that you probably do not even think about it when you are using it. The previous example probably did not even impress you. You are like Super Man: when he is rescuing a jumbo jet full of passengers he never seems to stop and think, “Oh, wow! I am actually flying.” He is so focused on using his powers that he never stops to think how awesome they really are.
Use your Super Power!
Try this example from the Veritas Prep Word Problems book. Use your Super Power and create an equation. (If you are having trouble making the equation just remember to find two things that are each equal to a third thing. Drop the thing they have in common and set the other two parts equal to each other).
“Machines A and B always operate independently at their respective constant rates. When working alone machine A can fill the production lot in 5 hours, and machine B can fill the production lot in X hours. Together they can fill the production lot in 2 hours. What is the value of X?
A) 3 1/3
C) 2 1/2
D) 2 1/3
E) 1 1/2”
What are the two things that you can set equal to each other? Let’s start with what you know. You know that the rate of A is 1 / 5 (of the job per hour). The rate of B is 1 / X (of the job per hour) and the rate of the two together (the rate of A + B) = 1 / 2 (of the job per hour).
Do you see it now? You know that the rate of A + B is 1 / 2. You can also add the individual rates of A and B, so that (the rate of A) + (rate of B) = 1 / 5 + 1/ X. You now have two different values that is each equal to the rate of A + B. Now you can set them equal to each other. So that “1 / 5 + 1 / X = 1 / 2” (the rate of A) + (the rate of B) = the rate of (A + B).
Now you have an equation that you can solve and the rest is Algebra. Find a common denominator for 5 and 2 so that the equation becomes “2 / 10 + 1 / X = 5 / 10.” 1 / X must equal 3 / 10. That means 3X = 10 and X = 3 1/3. The correct answer is A.
You and I might not be quite up to the status of theoretical physicists Sheldon and Koothrappali, but we do have something in common with them. We have the Power to create equations, meaning that we are super heroes, too!
David Newland has been teaching for Veritas Prep since 2006, and he won the Veritas Prep Instructor of the Year award in 2008. Students’ friends often call in asking when he will be teaching next because he really is a Veritas Prep and a GMAT rock star! Read more of his articles here.