Hi gmat_guy666,

This is a great "concept" question, meaning that you can get most of the way through it without doing too much physical work (as long as you understand the concepts within the question).

We're told that there are C women and D men. We're asked if the women earn an average annual salary > $25,000. This is a YES/NO question.

Fact 1: Total pay for all employees = $30,000(C+D) annually.

This gives us almost no information. Even if we had the values for C and D, we still wouldn't know the average salary for the women.
Fact 1 is INSUFFICIENT.

Fact 2: The men earn an average annual salary of $34,000.

Just like Fact 1, this doesn't give us much information. We know nothing about the number of women or their salaries.
Fact 2 is INSUFFICIENT.

Combined, we know....
Total pay = $30,000(C+D)
Average pay for Men = $34,000

If you're comfortable with the concept behind weighted averages, you might see that this is INSUFFICIENT (as the number of men increases, the average pay for women decreases). Here's how you can prove it though (by TESTing VALUES):

If....
C=1
D=1
Total pay = 30,000(2) = 60,000
Avg. pay for Men = 34,000
Avg. pay for Women = 26,000
The answer to the question is YES

C=1
D=2
Total pay = 30,000(3) = 90,000
Avg. pay for Men = 34,000 x 2 men
Avg. pay for Women = 22,000 x 1 woman
The answer to the question is NO

Combined, INSUFFICIENT

Final Answer: E

GMAT assassins aren't born, they're made,
Rich