the mean of a , b ,c is 6 ; and that of c , d ,e is 7 and that of a ,b ,c ,d ,e is 6.4.
Find c.
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f3 數字既mean
2007-08-12 8:16 am
回答 (3)
2007-08-12 8:23 am
✔ 最佳答案
(a+b+c)/3 =6a+b+c=18 --------->(1)
(c+d+e)/3 =7
c+d+e=21 --------->(2)
(a+b+c+d+e)/5=6.4
a+b+c+d+e=32 --------->(3)
(1) +(2) : a+b+2c+d+e=39 -----> (4)
(4)-(3) : c=7
參考: me
2007-08-12 7:25 pm
(a+b+c)/3 = 6
a+b+c=18
(c+d+e)/3 = 7
c+d+e=21
(a+b+c+d+e)/5 = 6.4
a+b+c+d+e = 32
(a+b+c+d+e)-(a+b+c)-(c+d+e) =32-21-18
-c = -7
c=7
a+b+c=18
(c+d+e)/3 = 7
c+d+e=21
(a+b+c+d+e)/5 = 6.4
a+b+c+d+e = 32
(a+b+c+d+e)-(a+b+c)-(c+d+e) =32-21-18
-c = -7
c=7
2007-08-12 8:27 am
(a+b+c)/3 = 6
a+b+c=18
(c+d+e)/3 = 7
c+d+e=21
(a+b+c+d+e)/5 = 6.4
a+b+c+d+e = 32
(a+b+c+d+e)-(a+b+c)-(c+d+e) =32-21-18
-c = -7
c=7
a+b+c=18
(c+d+e)/3 = 7
c+d+e=21
(a+b+c+d+e)/5 = 6.4
a+b+c+d+e = 32
(a+b+c+d+e)-(a+b+c)-(c+d+e) =32-21-18
-c = -7
c=7
收錄日期: 2021-04-18 23:08:53
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20070812000051KK00120