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by Rich Cohen, EMPOWERgmat.com [email protected]
This series of emails and PMs focuses on situations that many Test Takers face during their studies. The names of the original posters have been changed to protect their identities.
Raising High-600s Scores to 700+ Scores
Rich,
I have been preparing hard for the GMAT for the last couple of months (worked about 170 hours total). My last few test scores look something like this- 680, 680, 700, 670, 690. I seem to have plateaued. I really wish to breach the 700 score consistently. What are the best options in the market that can help me tackle the 700+ level questions with much ease?
Yul,
Hi Yul,
To start, it’s quite likely that another book is NOT what you need. At your current scoring level, the GMAT becomes really ‘sensitive’ to silly/little mistakes. When reviewing your CATs, it’s important to define WHY you’re getting questions wrong. On any of these CATs, did you get more questions wrong because of a silly/little mistake or because the question was too hard? Working through another book will likely not help you in either case, but learning/practicing the proper Tactics likely would help you a great deal. If ‘your way’ of approaching questions allows for too many little mistakes to occur, then a 700+ score will simply be impossible to achieve. Investing in some non-book resources and learning/practicing those Tactics consistently will likely help you to increase your score well into the 750+ range.
Avoiding Calculations That The GMAT Would NEVER Expect You to Do
Dear Rich,
How am I supposed to answer questions that use these types of exponents/roots?
Is 4^(1/2) + 4^(1/3) + 4^(1/4), then value of M is?
1) less than 3
2) Equal to 3
3) btw 3 and 4
4) equal to 4
5) greater than 4
Zephyr,
Hi Zephyr,
The GMAT will NOT require that you calculate fractional "cube-roots" or fractional "quad-roots", so that's not what you should do here.
Notice how the answer choices are all "ranges"; that means that we can probably estimate the correct answer.
4^(1/2) = 2 (that calculation is easy)
By comparison, 1^(1/3) = 1 and 8^(1/3) = 2, so…
4^(1/3) is between 1 and 2
Also by comparison, 1^(1/4) = 1 and 16^(1/4) = 2, so….
4^(1/4) is between 1 and 2
So, adding these values up gives us…
2 + (a number between 1 and 2) + (a number between 1 and 2) =
A total that is greater than 4.
Final Answer: E
The Answer Choices Can Provide a BIG Clue in How to Answer the Question
Hi Rich,
I know how to solve this question with algebra. What can I do to speed up on questions that have so many steps though?
If 1/2 of the air in a tank is removed with each stroke of a vacuum pump, what fraction of the original amount of air has been removed after 4 strokes?
(A) 15/16
(B) 7/8
(C) 1/4
(D) 1/8
(E) 1/16
Anka
Hi Anka,
You would likely find it faster to NOT do algebra here. Since we don't know how much air we're starting with, the tank could technically have any amount of air – thus we can TEST a Value. Instead of randomly choosing a value though, you should take a quick look at the answer choices. Notice how the common-denominator is 16? THAT number will likely be the best choice for your starting value.
Now, all you have to do is the basic "math", removing half after each stroke (with 4 strokes total):
Start = 16
remove half = 16 - 8 = 8
remove half = 8 - 4 = 4
remove half = 4 - 2 = 2
remove half = 2 - 1 - 1
So, 1/16 is left and 15/16 is removed.
GMAT assassins aren't born, they're made,
Rich
