Hi guerrero,
This is an example of a Roman Numeral question; a rather effective way to crush them is to prove the "opposite" of what the question asks for and then eliminate answer choices.
In this case, we know that y cannot be 3 and that 3x/y is a prime > 2
The questions asks for what MUST be true....so I'm going to prove what's NOT NECESSARILY TRUE...
I. x = y
Does x HAVE TO = y?
Can you come up with ANY situation in which that's not true?
How about...
x = 5/3
y = 1
We've satisfied all of the conditions and proven that x doesn't have to equal y.
Eliminate B and E
II y = 1
Does y HAVE TO = 1?
How about...
x = 2
y = 2
We've satisfied all of the conditions and proven that y doesn't have to = 1.
Eliminate C
III x and y are prime integers
How about...the example we used in Roman numeral 1
x = 5/3
y = 1
Eliminate D (we eliminated E earlier)
Final Answer is A
GMAT assassins aren't born, they're made,
Rich
