Rainman91 wrote:
I have a question. Some say that you should check from E and go above. Some say check C. Others say B and D. There is no hard rule for this. But assuming we are pressed for time and we stick to checking C first. How do we finish under 3 minutes?
Hi Rainman91,
You're asking about two different things, so we'll start with your first question (although it doesn't quite fit with how this question is written). When you face a prompt in which you can TEST THE ANSWERS, the answer choices are almost always written in order (either from least-to-greatest or greatest-to-least) - so if you can determine that an answer is 'too big' or 'too small', then you can eliminate multiple answers (for also being too big or too small). Here though, the answers are NOT written in order (Answers A, B and C get progressively larger, but then D and E are both smaller than Answer A). The answer that you might choose to start with will depend on how the prompt is written (and in some cases, even in how the answer choices are written).
As far as how to work through this question in an efficient fashion (and not spend upwards of 3 minutes on it): like many GMAT questions, this prompt isn't really about doing lots of math - it's about organizing the information that you're given so that you can avoid doing lots of calculations.
Notice how the first disc is $15.95? That's $0.05 LESS than $16.
Notice how the additional discs are all $3.99? That's $0.01 LESS than $4 for each additional disc.
It's interesting that the question tells us that after the first disc is purchased, EXACTLY 5 additional discs are purchases. The total of those 5 additional discs would be $0.05 less than $20. Thinking in these terms (the $0.05 'pieces' that you have to subtract from the 1st disc and the sum of the next 5 discs), the numbers in this prompt are actually pretty easy to combine and simplify.
GMAT assassins aren't born, they're made,
Rich
Contact Rich at: Rich.C@empowergmat.com