GMAT Tip of the Week Evolving Your GMAT Quant Score with Help from The Evolution Of Rap

If its March, it must be Hip Hop Month at the GMAT Tip of the Week space, where this year weve been transfixed by Voxs video on the evolution of rhyme schemes in the rap world. The video below (which is absolutely worth a watch during a designated study break) explores the way that rap has evolved from simple rhyme schemes (yada yada yada Bat, yada yada yada Hat, yada yada yada Rat, yada yada yada Cat) to the more complex wait did he just say what I thought he said? inside-out rhyme schemes that make you rewind an Eminem or Kendrick Lamar track because your ears must be playing tricks on you. And if you dont have the study break time right now, well summarize. While a standard rhyme might have a one-syllable rhyme at the end of each bar (do you like green eggs and HAM, yes I like them Sam I AM), rappers have continued to evolve to the point where nowadays each bar can contain multiple rhyme schemes. Consider Eminems Lose Yourself: Snap back to reality, oh there goes gravity Oh there goes Rabbit he choked, hes so mad but he wont Give up that easy, nope, he wont have it he knows His whole backs to these ropes, it dont matter hes dope He knows that but hes broke, hes so stagnant he knows Where gravity, Rabbit, he, mad but he, that easy, have it he, backs to these, matter hes, that but hes, and stagnant, he all rhyme with one another, the list of goes/goes/choked/so/wont/knows/whole/ropes/dont/dope keeps that hard O sound rhyming consistently throughout, too. And that was 15 years agosince them, Eminem, Kendrick, and others have continued to build elaborate rhyme schemes that reward those listeners who dont  just listen for the simple rhyme at the end of each bar, but pick up the subtle rhyme flows that sometimes dont come back until a few lines later. So what does this have to do with your GMAT score? One of the most common study mistakes that test-takers make is that they study skills as individual, standalone entities, and dont look for the subtle ways that the GMAT testmaker can layer in those sophisticated Andre-3000-style combinations. Consider an example of an important GMAT skill, the Difference of Squares rule that (x + y)(x y) = x^2 y^2. A standard (think early 1980s Sugarhill Gang or Grandmaster Flash) GMAT question might test it in a relatively obvious way: What is the value of (x + y)? (1) x^2 y^2 = 0 (2) x does not equal y Here if you factor Statement 1 youll get (x + y)(x y) = 0, and then Statement 2 tells you that its not (x y) that equals zero, so it must be x + y. This Data Sufficiency answer is C, and the test is essentially just rewarding you for knowing the Difference of Squares. The GMAT it cares bout the Difference of Squares When theres squares and subtraction Put this rule into action A slightly more sophisticated question (think late 1980s/early 1990s Rob Bass or Run DMC) wont so obviously show you the Difference of Squares. It might hide that behind a square that  few  people tend to see as a square, the number 1: If y = 2^(16) 1, the greatest prime factor of y is: (A) Less than 6 (B) Between 6 and 10 (C) Between 10 and 14 (D) Between 14 and 18 (E) Greater than 18 Here, many people dont recognize 1 as a perfect square, so they dont see that the setup is 2^(16) 1^(2), which  can be factored as: (2^8 + 1)(2^8 1) And that 2^8 1 can be factored again, since 1 remains 1^2: (2^8 + 1)(2^4 + 1)(2^4 1) And that ultimately you could do it again with 2^4 1 if you wanted, but you should know that 2^4 is 16 so you can now get to work on smaller numbers. 2^8 is 256 and 2^4 is 16, so you have: 257 * 17 * 15 And what really happens now is that you have to factor out 257 to see if you can break it into anything smaller than 17 as a factor (since, if not, you can select greater than 18). Since you cant, you know that 257 must have a prime factor greater than 18 (it turns out that its prime) and correctly select E. The lesson here? This problem directly tests the Difference of Squares (you dont want to try to calculate 2^16, then subtract 1, then try to factor out that massive number) but it does so more subtly, layering it inside the obvious prime factor problem like a rapper might embed a secondary rhyme scheme in the middle of each bar. But in really hard problems, the testmaker goes full-on Greatest of All Time rapper, testing several things at the same time and rewarding only the really astute for recognizing the game being played. Consider: The size of a television screen is given as the length of the screen’s diagonal. If the screens were flat, then the area of a square 21-inch screen would be how many square inches greater than the area of a square 19-inch screen? (A) 2 (B) 4 (C) 16 (D) 38 (E) 40 Now here you KNOW youre dealing with a geometry problem, and it also looks like a word problem given the television backstory. As you start calculating, youll know that you have to take the diagonal of each square TV and use that to determine the length of each side, using the 45-45-90 triangle ratio, where the diagonal = x√2. So the length of a side of the smaller TV is 19/√2 and the length of a side of the larger TV is 21/√2. Then you have to calculate the area, which is the side squared, so the area of the smaller TV is (19/√2)^2 and the area of the larger TV is (21/√2)^2. This  is starting to look messy (Who knows the squares for 21 and 19 offhand? And radicals in denominators never look fun) UNTIL you realize that you have to subtract the two areas. Which means that your calculation is: (21/√2)^2 (19/√2)^2 This  fits perfectly in the Difference of Squares formula, meaning that you can express x^2 y^2 as (x + y)(x y). Doing that, you have: [(21 + 19)/√2][(21-19)/√2] Which is really convenient because the math in the numerators is easy and leaves you with: (40/√2) * (2/√2) And when you multiply them, the √2 terms in the denominators square out to 2, which factors with the 2 in the numerator of the right-side fraction, and everything simplifies to 40. And then, in classic oh this guys effing GOOD hip-hop style (like in the Eminem lyric youre witnessing a massacre like youre watching a church gathering take place and you realize that hes using massacre and mass occur the church gathering taking place simultaneously), you realize that you should have seen it coming all along. Because when you subtract the area of one square minus the area of another square youre LITERALLY taking the DIFFERENCE of two SQUARES. So whats the point? Too often people study for the GMAT like theyd listen to 1980s rap. They expect the Difference of Squares to pair nicely at the end of an Algebra-with-Exponents bar, and the Isosceles Right Triangle formula to pair nicely with a Triangle question. They learn skills in distinct silos, memorize their flashcards in nice, tidy sets, and then go into the test and realize that theyre up against an exam that looks a lot more like a 2017 mixtape with layers of rhyme schemes and motives. You need to be prepared to use skills where they dont seem to obviously belong, to jot down and rearrange your scratchwork, label your unknowns, etc., looking for how you might reposition the math youre given to help you bring in a skill or concept that youve used countless times, just in totally different contexts. The GMAT testmaker has a much more sophisticated flow than the one youre likely studying for, so pay attention to that nuance when you study and youll have a much better chance of keeping your score 800. Getting ready to take the GMAT? We have free online GMAT seminars running all the time. And as always, be sure to follow us on  Facebook, YouTube,  Google+  and Twitter! By Brian Galvin.