中一數學題
2008-04-27 7:11 pm
In 3 consecutive number , the smallest number is 19/20 of the largest one , find the middle number .
回答 (3)
2008-04-29 2:32 am
✔ 最佳答案
let x be the middle number among the threex-1 = 19
----- ----
x+1 20
20(x-1)=19(x+1)→交叉相乘 將x-1乘落20到 x+1就乘19
20x-20=19x+19
20x-19x=19+20
x=39
so the middle numeber is 39
2008-04-27 7:30 pm
let n be the middle number
(n-1)/(n+1)=19/20
20(n-1)=19(n+1)
20n-20=19n+19
n=20+19=39
(n-1)/(n+1)=19/20
20(n-1)=19(n+1)
20n-20=19n+19
n=20+19=39
2008-04-27 7:24 pm
Let the middle number be X,
(largest nimber = X 1, smallest number =X-1)
X-1 = (X 1)*19/20
20(X-1) = 19(X 1)
20X-20 = 19X 19
20X-39 = 19X
X=39
the middle number is 39.
2008-04-27 11:24:43 補充：
(largest number = X+1)
(largest nimber = X 1, smallest number =X-1)
X-1 = (X 1)*19/20
20(X-1) = 19(X 1)
20X-20 = 19X 19
20X-39 = 19X
X=39
the middle number is 39.
2008-04-27 11:24:43 補充：
(largest number = X+1)
收錄日期: 2021-04-15 14:58:30
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20080427000051KK00862