题库搜索>问题求解PS-13693
If a and b are positive integers such that a – b and a/b are both even integers, which of the following must be an odd integer?
分析A选项
分析B选项
分析C选项
分析D选项
分析E选项
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a-b为偶数---->a、b同奇同偶
a/b为偶数---->a一定为偶数
所以a、b一定为偶数
因为a=b*偶数
所以a一定是4的倍数
A a/2一定是偶数
B b/2 可奇可偶
C （a+b）/2 可奇可偶
D （a+2）/2=a/2+1 一定是奇数
E （b+2）/2=b/2+1 可奇可偶
所以选D
626617yh
a-b=2k; a/b=2n; (b+2k)/b=2n b是偶数 代入就得答案了
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2021-03-28 20:11:51
Kath1230
这里不是说b也是偶数吗？为什么(b+2)/2不是奇数呢？
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2019-01-06 15:45:12
月冷隐回复Kath1230
b=2和b=4，结果不同的。
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2019-06-15 15:42:07
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