Let a be the average of 20 numbers whose average does not exceed 5. Let b be the average of rest of the 10 numbers. Clearly, b>5 i.e. the average of these numbers exceeds 5 Therefore, 30×5=20a+10b ⇒2a+b=15 ⇒b=15−2a Going by the options, we can say that when a=4.5,b=6 which satisfies all the conditions.