题干

某家电专卖店试销A,B,C三种新型空调,销售情况记录如表:

第一周

第二周

第三周

第四周

第五周

A型数量(台)

10

10

15

A4

A5

B型数量(台)

10

12

13

B4

B5

C型数量(台)

15

8

12

C4

C5

(Ⅰ)为跟踪调查空调的使用情况,根据销售记录,从该家电专卖店前三周售出的所有空调中随机抽取一台,求抽到的空调“是B型空调或是第一周售出空调”的概率;

(Ⅱ)为跟踪调查空调的使用情况,根据销售记录,从该家电专卖店第二周和第三周售出的空调中分别随机抽取一台,求抽取的两台空调中A型空调台数X的分布列和数学期望.

上一题 下一题 0.0难度 选择题 更新时间:2019-05-10 09:01:34

答案(点此获取答案解析)

解:(I)方法1:从前三周售出的所有空调中随机抽取一台,有105种可能,其中“是B型或是第一周售出空调”有35+35﹣10=60.

因此抽到的空调“是B型或是第一周售出空调”的概率是 P=60105=

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