[問題] 一題排列組合
(這題答案是3、5)
想分別問一下1、2、4選項
1:解答是說要以女生人數分類,分情況下去算(分別是女2人、女3人、女4人及女5、6人
)
但一開始看到選項的算法覺得很合理就選了,請問選項算法是錯在哪呢?
2:答案是選項答案再乘上1/2,為什麼要乘上1/2?
4:這題就看不太懂了
解答是 把選項答案再乘上1/2
想請高手幫忙解釋一下
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推
06/09 16:46, , 1F
06/09 16:46, 1F
可是C9取3裡的9 有包含剩下的4位女生欸~
※ 編輯: gash55025502 (1.200.52.78), 06/09/2016 16:55:07
推
06/09 16:56, , 2F
06/09 16:56, 2F
→
06/09 16:56, , 3F
06/09 16:56, 3F
→
06/09 16:56, , 4F
06/09 16:56, 4F
→
06/09 16:57, , 5F
06/09 16:57, 5F
推
06/09 16:58, , 6F
06/09 16:58, 6F
→
06/09 16:58, , 7F
06/09 16:58, 7F
→
06/09 16:59, , 8F
06/09 16:59, 8F
→
06/09 16:59, , 9F
06/09 16:59, 9F
→
06/09 16:59, , 10F
06/09 16:59, 10F
→
06/09 16:59, , 11F
06/09 16:59, 11F
→
06/09 16:59, , 12F
06/09 16:59, 12F
推
06/09 17:00, , 13F
06/09 17:00, 13F
→
06/09 17:00, , 14F
06/09 17:00, 14F
推
06/09 17:03, , 15F
06/09 17:03, 15F
→
06/09 17:03, , 16F
06/09 17:03, 16F
→
06/09 17:03, , 17F
06/09 17:03, 17F
推
06/09 17:04, , 18F
06/09 17:04, 18F
→
06/09 17:18, , 19F
06/09 17:18, 19F
→
06/09 17:20, , 20F
06/09 17:20, 20F
→
06/09 17:21, , 21F
06/09 17:21, 21F
→
06/09 17:22, , 22F
06/09 17:22, 22F
→
06/09 17:23, , 23F
06/09 17:23, 23F
→
06/09 17:24, , 24F
06/09 17:24, 24F
→
06/09 17:24, , 25F
06/09 17:24, 25F
推
06/09 19:15, , 26F
06/09 19:15, 26F
→
06/09 19:15, , 27F
06/09 19:15, 27F
→
06/09 19:15, , 28F
06/09 19:15, 28F
→
06/09 19:15, , 29F
06/09 19:15, 29F
→
06/09 19:15, , 30F
06/09 19:15, 30F
推
06/09 19:17, , 31F
06/09 19:17, 31F
→
06/09 19:17, , 32F
06/09 19:17, 32F
→
06/09 19:20, , 33F
06/09 19:20, 33F
→
06/09 19:20, , 34F
06/09 19:20, 34F
→
06/09 19:20, , 35F
06/09 19:20, 35F
→
06/09 19:25, , 36F
06/09 19:25, 36F
→
06/09 19:25, , 37F
06/09 19:25, 37F
→
06/09 19:25, , 38F
06/09 19:25, 38F
→
06/09 19:25, , 39F
06/09 19:25, 39F
→
06/09 19:25, , 40F
06/09 19:25, 40F
→
06/09 19:25, , 41F
06/09 19:25, 41F
→
06/09 19:26, , 42F
06/09 19:26, 42F
→
06/09 19:26, , 43F
06/09 19:26, 43F
→
06/09 19:27, , 44F
06/09 19:27, 44F
→
06/09 19:27, , 45F
06/09 19:27, 45F
謝謝樓上各位的回答~也有很熱心的版友站內信來說明!我大致上都懂了,感覺來問一次
學到很多,哈哈哈
※ 編輯: gash55025502 (1.200.52.78), 06/09/2016 22:01:17
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