if a cage contains 100 mice, 3 of which are male, what is the probability that the 3 male mice will be included if 10 mice are randomly selected ?
2007-02-19 18:48:23 · 3 個解答 · 發問者 guess 2 in 科學 ➔ 數學
全部選法 C(100, 10)
3 隻 male 被選中 C(3,3)*C(97,7)
機率 = C(3,3)*C(97,7)/C(100,10)
= [97!/(90!*7!)]/[100!/(90!*10!)]
= 10*9*8/(100*99*98)
= 2/2695
如果有問題, 請來函討論. 不然, 我可能會錯失你再補充的疑點.
2007-02-19 20:24:42 · answer #1 · answered by JJ 7 · 0⤊ 0⤋
2位都回答的都是對的~so我也不知道該選誰,就讓大家來決定吧~,
最後還是要謝謝你們2位~
2007-02-20 10:27:01 · answer #2 · answered by guess 2 · 0⤊ 0⤋
C十取三分之C一百取三 = 10.9.8/ 100.99.98 =2 / 2695 =0.0007421
2007-02-20 14:22:03 補充：
對ㄌ 我也來補充我是誰ˊˋ 我是整天睡懶覺的高三生
ㄏ u喔 不懂記得可以密我 一起討論ㄅ@@
2007-02-19 19:00:08 · answer #3 · answered by ? 3 · 0⤊ 0⤋