SAT数学真题
问题描述：
SAT数学真题
The least and greatest numbers in a list of 7
real numbers are 2 and 20,respectively.The median of the list is 6,and the
number 3 occurs most often in the list.Which of the following could be the
average (arithmetic mean) of the numbers in the list?
I.7 II.8.5 III.10
A.I only B.I and II only C.I and III only D.II and III only E.I,II and III
答
答案选E 第一个是2最后一个是20第四个是6,因为3出现最多所以第二三个都是3.
假设平均值为7 七个数和为49则第六个为7第八个为8即可
假设平均值为10 17、19即可
既然7可以10可以那么8.5也可以
所以选E