Let a be the average of 20 numbers whose average does not exceed 5.
Let b be the average of the remaining 10 numbers. It is evident that \(b>5\), meaning the average of these numbers exceeds 5.
Therefore, \(30×5=20a+10b\), which simplifies to \(2a+b=15.\)
This equation leads to \(b=15−2a.\)
Considering the given options, when \(a=4.5, b=6\), satisfying all the given conditions.