numbers is 2/3 of the middle one. Find the middle number.
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更新2:
s0rry-.- 係雙數
F.1方程問題(英文)
2009-11-24 5:48 am
1.There are 3 consecutive numbers.The sum of the smallest and the largest
numbers is 2/3 of the middle one. Find the middle number.
numbers is 2/3 of the middle one. Find the middle number.
回答 (4)
2009-11-24 5:59 am
✔ 最佳答案
the middle number=02009-11-23 21:59:25 補充：
Let the 3 consecutive numbers be x,x+1and x+2.
x+(x+2)=2/3 (x+1)
2x+2=2/3x +2/3
4/3x=-4/3
x=-1
The middle number is 0.
2009-11-23 22:55:38 補充：
3個連續雙數？?????
2009-11-24 11:03 pm
3個連續數(無論雙數, 單數, 或 以k遞增, i.e. x, x+k, x+2k), 首尾兩數相加必定是中間數之2倍, 不會是2/3, 是否出錯題目??
2009-11-24 6:25 am
0 is an even number
2009-11-24 6:21 am
Let the smallest number is a,
then the mddle one is (a + 2),
the largest one is (a + 4)
a + (a + 4) = 2/3 x (a + 2)
2a + 4 = 2(a + 2) / 3
3(2a + 4) = 2(a + 2)
6a + 12 = 2a + 4
4a = -8
a = -2
So,
the middle one = (-2) + 2 = 0
then the mddle one is (a + 2),
the largest one is (a + 4)
a + (a + 4) = 2/3 x (a + 2)
2a + 4 = 2(a + 2) / 3
3(2a + 4) = 2(a + 2)
6a + 12 = 2a + 4
4a = -8
a = -2
So,
the middle one = (-2) + 2 = 0
收錄日期: 2021-04-22 00:49:55
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https://hk.answers.yahoo.com/question/index?qid=20091123000051KK01406