Question

已知每枚導(dǎo)彈擊中飛機的概率為0.6，欲以99%的把握擊中來犯的一架敵機，需發(fā)射導(dǎo)彈的枚數(shù)為(    )

A.3                     B.4                 C.5                 D.6

Answer 1

解析:由1-0.4^x=0.99，得x=6.

答案:D