问题 解答题

为援助汶川灾后重建,对某项工程进行竞标,共有6家企业参与竞标.其中A企业来自辽宁省,B、C两家企业来自福建省,D、E、F三家企业来自河南省.此项工程需要两家企业联合施工,假设每家企业中标的概率相同.

(Ⅰ)企业E中标的概率是多少?

(Ⅱ)在中标的企业中,至少有一家来自河南省的概率是多少?

答案

(Ⅰ)由题意知本题是一个古典概型,

试验发生包含的事件是从这6家企业中选出2家,选法有(A,B),(A,C),(A,D),

(A,E),(A,F),(B,C),(B,D),(B,E),(B,F),(C,D),(C,E),

(C,F),(D,E),(D,F),(E,F),共有15种.

其中企业E中标的选法有(A,E),(B,E),(C,E),(D,E),(E,F),共5种,

∴企业E中标的概率为

5
15
=
1
3

(Ⅱ)由题意知本题是一个古典概型,试验发生包含的事件是在中标的企业中,

没有来自河南省选法有:(A,B),(A,C),(B,C)共3种.

∴“在中标的企业中,没有来自河南省”概率为

3
15
=
1
5

∴“在中标的企业中,至少有一家来自河南省”的概率为1-

1
5
=
4
5

不定项选择
阅读理解

American women experience a great variety of lifestyle. A typical American woman may be single. She may also be divorced or married. She may be a homemaker, a doctor or a factory worker. It is very difficult to generalize about American women. However, one thing that many American women have in common is their attitudes about themselves and their roles in American life.

Historically, American women have always been very independent. The first settlers to come to New England were ten young couples that had left behind their extended families. The women were alone in a new, undeveloped country with their husbands. This has two important effects. First of all, this was the uncivilized environment that demanded every person to share in developing it and in survival. Women worked with their husbands and children to make themselves accepted in this new land. Second, because they were in a new land without the established influence of older members of society, women felt free to step into non—traditional roles.

This role of women was strengthened in later years as Americans move west again, leaving families behind and meeting a new environment. Even later, in the east, as new settlers arrived, women often found jobs more easily than men. Women became the supporters of the family.

Within the established lifestyle of the industrialized twentieth century, the strong role of women was not attractive as in the early days of the country. Some women stepped into the men’s jobs as factory and business workers. After the war, some women stayed in these positions, and others left their jobs with a new sense of ability.

小题1:A typical American woman is______________.

A.single or married

B. divorced

C.sure about herself and her role

D. all of the above小题2: During the industrialized twentieth century, the role of women__________.

A.was found out

B.was as important as before.

C.declined

D.was stronger than that of the early days小题3: Women took part in men’s job during the time of_________.

A.the Second World War

B. the Westward Movement

C. the early immigration

D. the industrialized twentieth century.