Hi april24,
TESTing VALUES (the approach Brent used) is perfect for this question, so I won't rehash any of that here. Instead, I'll offer some insight into these types of questions.
Most Roman Numeral questions are based on Number Properties (the little rules that define how numbers "work", interact, etc.); if you know these rules, then you can move through Number Property questions rather quickly.
Here, we're told that X is POSITIVE, but that doesn't necessarily mean that X is an integer. We have to be THOROUGH to get the correct answer.
X could be ANYTHING POSITIVE, including fractions, 1, other integers, etc. so we have to do enough work to prove which Roman Numerals are possible and which is not.
The number properties that I see:
1) When X = 1, X^2 and 1/X are equal; since we're dealing with inequalities, using 1 is NOT an option
2) When X = a positive fraction, X^2 makes the number SMALLER; 1/X makes the number BIGGER
3) When X = an Integer > 1, X^2 makes the number BIGGER, 1/X makes the number SMALLER
4) When X = anything, 2X makes the number TWICE as BIG
With these rules and TESTing some values, you can easily get the correct answer.
GMAT assassins aren't born, they're made,
Rich
