Hi All,
This is a great Number Property question; even if you don't immediately recognize the Number Properties involved, you can still discover the patterns (although it might take a little work).
We're told that X and Y are PRIME NUMBERS. We're asked if Y(X-3) is ODD. This is a YES/NO question.
Fact 1: X > 10
Since we know that X is PRIME, this Fact tells us that X must also be ODD. Y can be ANY PRIME number....
IF....
X = 11
then (X-3) = (11-3) = 8
(any prime)(8) will be EVEN, so the answer to the question is NO.
IF....
X = 13
then (X-3) = (13-3) = 10
(any prime)(10) will be EVEN, so the answer to the question is NO.
IF....
X = 17
then (X-3) = (17-3) = 14
(any prime)(14) will be EVEN, so the answer to the question is NO.
This pattern continues on; the answer to the question is ALWAYS NO.
Fact 1 is SUFFICIENT
Fact 2: Y < 3
Since Y is PRIME, we know that Y MUST be 2. X can be ANY PRIME number....
IF....
Y = 2 and X = ANY PRIME
then (X-3) = an integer
(2)(any integer) will be EVEN, so the answer to the question is ALWAYS NO.
Fact 2 is SUFFICIENT
Final Answer:
GMAT assassins aren't born, they're made,
Rich