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【OG20-P276-275题】
Of a group of 50 households, how many have at least one cat or at least one dog, but not both?
(1)The number of households that have at least one cat and at least one dog is 4
(2)The number of households that have no cats and no dogs is 14
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假设A=at least one cat,but not both;B=at least one dog, but not both
both部分是x,neither部分是y
A+B+x+y=50,所求的就是A+B
条件1:x=4,不充分
条件2:y=14,不充分
结合起来:A+B+4+14=50,A+B=22,充分
题目讨论 (3条评论)

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冲他丫的
这样啊 条件1理解错了
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0 回复 2021-10-17 17:15:03
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Layla42
没养猫也没养狗的家庭是14, 就有50-14=36家至少养了猫或狗, 4家养了猫和狗, 答案就是36-4=32
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1 回复 2019-03-29 10:09:45
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Alisizz
问 at least one cat or at least one dog, but not both? dog none-dog tot cat 4 x none-cat y 14 tot 50 x+y = 32
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0 回复 2017-12-26 10:04:30