b**********y
发帖数: 90 | 1 有 9张纸牌，分别为1至9。A、B、C、D四人取牌，
每人取2张。现已知 A取的两张牌之和是10; B取的两张
牌之差是1; C取的两张牌之积是24; D取的荫张牌之商
是3。 请说出他们四人各拿了哪两张纸牌;剩下的一
张又是什么牌? | s*********r
发帖数: 869 | 2 c's combine choices are fewest so start from c: 3,8 or 4,6
suppose 3,8 first, then d must be 2,6, then a have to be 1 and 9, finally,
b has 4 and 5. the remaining number is 7
suppose c is 4 and 6, then d can be (1,3) or (3,9). suppose d is (1,3) first,
a is (2,8), the remaining are 5,7,9 can't be b. suppose d is (3,9), then
a has to be (2,8) again, the remaining are 1,5,7 still can't be included in b.
thus the answer is a(1,9), b(4,5), c(3,8), d(2,6). the remaining card is 7.
【在 b**********y 的大作中提到】
: 有 9张纸牌，分别为1至9。A、B、C、D四人取牌，
: 每人取2张。现已知 A取的两张牌之和是10; B取的两张
: 牌之差是1; C取的两张牌之积是24; D取的荫张牌之商
: 是3。 请说出他们四人各拿了哪两张纸牌;剩下的一
: 张又是什么牌?
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