某牧场的10头牛因误食疯牛病毒污染的饲料被感染,已知疯牛病发病的概率为0.02.

题型:选择题

问题:

某牧场的10头牛因误食疯牛病毒污染的饲料被感染,已知疯牛病发病的概率为0.02.若发病的牛数为ξ,则Dξ等于

A.0.2

B.0.196

C.0.8

D.0.812

考点:随机事件及其概率
题型:选择题

读下列对话,在横线上填上汤的价格。

Waiter: Hello! What would you like for lunch?

Jack: I'd like some rice and fish, please.

Waiter: Your rice and fish.

Jack: I'd 1ike some noodles and beef, please.

Waiter: Your noodles and beef.

Jack: Thank you.

Waiter: Anything else?

Jack: Some soup and vegetables, please.

Waiter: Your soup and vegetables. Here's your bill.

Jack: Oh... Forty yuan.

                         __________

题型:选择题

把-495°表示成k×360°+θ(k∈Z)的形式,则θ可以是(  )

A.-135°

B.45°

C.-225°

D.135°

题型:选择题

细菌的生殖方式是(  )

A.孢子生殖

B.有性生殖

C.分裂生殖

D.芽孢生殖

题型:选择题

将一定量的化学式为xFeSO4•y(NH42SO4.6H2O的晶体加入到过量的NaOH溶液中加热,得到NH30.85g(假如生成NH3的全部逸出),过滤、洗涤、灼烧,得到Fe2O3固体2.0g.则关于x、y关系正确的是(  )

A.x:y=1:1

B.x:y=1:2

C.x:y=1:4

D.x:y=2:

题型:选择题

知识改变命运,高考决定命运。你怎么看?

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