推 Austin9:謝謝lubu，蠻清楚的！ 07/02 23:29
: 8.A delegation of four students is to be selected from a total of 12 students
: to attend a meeting
: (a)in how many ways can the delegation be choosen?
: (B)repeat part (a) if there are two students who refuse to be in the
: delegation together?
: (c)repeat part(a) if there are two students who wil only attend the meeting
: together? will?
: (d)repeat part(a) if there are two students who refuse to be in the delegation
: together and two students who refuse to be in the delegation together?
: 我的想法b題答案是C(10,3)但ans是c(2,1)c(10,3)
(b)我覺得應該是c(2,1)c(10,3)+c(10,4)才對...
首先題目只說兩個學生拒絕一起出席 但不一定要挑這兩個學生 =>c(10,4)
若挑到其中一個 則另一個不會去所以是 c(2,1)c(10,3)
: 不懂c的答案是C(10,2)+C(10,4)
(c) 這題答案也是很怪 ....
已確定某兩個學生會一起參加meeting 所以應該是 c(10,2)就好
如果這是手抄的 可能答案抄錯題 把b小題的 c(10,4)抄到c小題去
然後d小題只抄到前半段.....
大概上課太累 囧
: 不懂d的答案是C(2,1)C(8,1)+C(2,1)C(8,3)(註:第d題的題目覺得應該是抄錯了，但我
: 手邊拿到的就是這樣)
(d)這題題目嗯.... 應該是有問題
參考看看
: 請各位高手解惑一下，謝謝。
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