x, 3, 1, 12, 8
If x is an integer, is the median of the 5 numbers showngreater than the average (arithmetic mean) of the 5 numbers?
(1) x > 6
(2) x is greater than the median of the 5 number
各位牛牛，请问解这类题目有没有什么简单的方法？
困扰已久~~~作者: UMHIVTDC 时间: 2012-11-27 19:39
是不是只能这么一个一个试呢？
把已知的数字排序
1, 3, 8, 12, ... X
median M
mean (1+3+8+12+x)/5
(1) x >6 if x=7 then M = 7 mean = 4.2
if x = 20 then M = 8 mean = 8.8 so (1) alone can't
(2) x greater than the median of the 5 number ==> x >8
if x = 9 then M =8 mean = 6.6
if x = 30 then M =8 mean = 10.8 so (2) alone can't either
(1)+(2) = (2)
so can't say weather median greater then mean.作者: chaomat1988 时间: 2012-11-29 06:31
看了你的解释我如梦初醒
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