Data Sufficiency (DS) | A certain list consists of 400 different numbers. Is the average......

If the original condition generally includes “rElation” of median, mean, standard deviation, etc, there is high chance that E is the correct answer.
Using both the condition 1) and the condition 2), we know 1)=2). Hence, the correct answer is D.
So, there always is a median in 280 numbers, and median<mean. The answer is yes and the condition is sufficient.
Please remember that if 1)=2), then D is the correct answer with 95% of chance.