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Re: If k is an integer and 121 < k^2 < 225, then k can have at most how
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28 Mar 2015, 12:38
Hi All,
It looks like everyone has properly answered this question, so I won't rehash an explanation here. Instead, I want to point out how the GMAT will repeated test you on how well you understand certain concepts by putting those concepts into different formats. In that way, you're tested on more than just 'math knowledge', you're tested on how well you can use that knowledge under different circumstances. In this case, the concept is 'squared terms.'
For example, I bet that everyone can answer the following equation:
X^2 = 25
You should recognize that there are 2 solutions to this equation: one positive and one negative. When you start to factor in inequalities or other math concepts (absolute values, Pythagorean Theorem, etc.), you have to consider even MORE possibilities.
For example...
Z^2 < 4
Here, there is a RANGE of values (positive, negative and 0).
Part of properly training for the GMAT is to develop the proper 'reaction' to seeing certain types of information. Here, seeing K^2 should make you think "there's probably more than just a positive answer"; seeing inequalities should make you think "there's probably multiple answers."
GMAT assassins aren't born, they're made
Rich