Question

A箱中裝有6張除顏色外完全相同的卡片，B箱中裝有5張除顏色外完全相同的卡片.現(xiàn)用0，1，2三個(gè)數(shù)字給卡片標(biāo)號(hào)，標(biāo)號(hào)結(jié)果如下表所示：

從A箱中任取兩張卡片，從B箱中任取1張卡片，用ξ表示取出的3張卡片上標(biāo)號(hào)的積.

（1）求P（ξ=0）的值；

（2）求ξ的數(shù)學(xué)期望.

Answer 1

解:(1)P(ξ=0)=1-.                                                                ?

=.                                                                                                                     ?

(2)∵P(ξ=2)==,                                                                                   ?

P(ξ=4)==,                                                                        ?

P(ξ=8)==,                                                                                              ?

∴Eξ===.