概率!!!!!

2007-10-04 5:55 am
電子工廠有兩條製造原子粒的生產線A和B,生產量的比是5:3。生產線A生產原子粒有60%上等,30%普通,10%低劣。生產線B生產原子粒有55%上等,40%普通,5%低劣。從工廠的原子粒中,抽2粒原子粒,求下列概率:
1.抽出兩個質素低劣的原子粒
2.2粒原子粒來自不同生產線,質素均上等的原子粒

回答 (2)

2007-10-04 7:24 am
✔ 最佳答案
1.
(5/8)*10% + (3/8)*5%
=0.0525 + 0.01875
= 0.07125

2.
[(5/8)*60%*(3/8)*55%]*2
= 99/640
= 0.1547

2007-10-03 23:26:36 補充:
1. 兩粒 ..... 應該 = 0.07125^2 = 0.005077

2007-10-03 23:28:44 補充:
1.加錯 .....0.0525 0.01875 = 0.08125兩粒即 0.08125^2 = 0.006602
2007-10-04 7:18 am
1.抽出兩個質素低劣的原子粒
(5/8)(10%) + (3/8)(5%) = 13/160
概率 (兩個質素低劣) = (13/160)^2 = 169/25600
2.2粒原子粒來自不同生產線,質素均上等的原子粒
(2)(5/8)(60%)(3/8)(55%) = 99/640


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