问题 问答题

某机电安装工程项目混凝土总需要量为5000m3,混凝土工程施工有两种方案可供选择:方案甲为现场制作;方案乙为购买商品混凝土。已知商品混凝土平均单价为410元/m3,现场制作混凝土的单价计算公式为:

式中 C——现场制作混凝土的单价(元/m3);

C1——现场搅拌站一次性投资(元),本案例C1为200000元;

C2——搅拌站设备装置的租金和维修费(与工期有关的费用),本案例C2为15000元/月;

C3——在现场搅拌混凝土所需费用(与混凝土数量有关的费用),本案例C3为320元/m3

Q——现场制作混凝土的数量;

T——工期(月)。

[问题]

当混凝土浇筑工期为12个月时,现场制作混凝土的数量最少为多少时才比购买商品混凝土经济?

答案

参考答案:

当工期为12个月时,现场制作混凝土的最少数量计算如下。

设最少数量为x,根据公式得出

即当T=12个月时,现场制作混凝土的数量最少为4222.22m3时才比购买商品混凝土经济。

阅读理解

BC Social Report, August 14, 2010

Scandinavians may spend a lot of the winter in darkness but they are the happiest people in Europe, according to a study showed this month. Countries like Denmark and Finland scored highest on the study of happiness in Europe carried out by Cambridge University, which also found that the sunny southern countries of Italy, Portugal and Greece got the least joy out of  life.

The survey entitled:  "No Man is an Island" showed that countries where people enjoy time with friends and family, have trust in government and national institutions were more likely to be happy than those living in a sunny climate. The study rated respondent on their overall sense of happiness and life satisfaction on a scale of one to 10.

Danes (丹麦人)--who expressed a high level of trust in their politicians and public institutions--came top of the field at 8.3. Italians--who reported lower levels of satisfaction with their national quality of government--came last at 6.49.' "Italy, Greece, Portugal, Germany and France report the lowest levels of happiness while the Scandinavian Countries, Netherlands and Luxembourg report the highest," the study said.

Although Europeans are generally four times wealthier than their fathers and grandfathers, their levels of happiness are either equal to or lower than 40 years ago. The study also looked at factors contributing to happiness within countries and surprisingly found that an interest in politics actually increased happiness.

Lead researcher Luisa Corrado said tax cuts and throwing money at social problems appeared to have no effect on the happiness of citizens when compared with government policies which strengthened and supported wider social networks.  "People are less naive ( 质朴的) than one would expect, politicians need to adapted their policies and target specific problems in specific areas," she said.

小题1: According to the passage, we can know        .

A.Scandinavians are the happiest people in the world

B.the research is carried out by Oxford University

C.the people of the northern countries are much happier

D.Italians expressed their trust in politics and institutions小题2:Which of the following factors increases happiness?

A.Interest in polities

B.Wealth

C.Health

D.Websites.小题3:The underlined word "scale" in the second paragraph means                  

A.sense

B.life

C.report

D.range小题4: What's the writer's attitude to the study?

A. Subjunctive.          B. Objective.    C. Pessimistic.    D: Optimistic.

小题5:In what column may readers probably read the passage?

A.Lifestyle.

B.Amusement.

C.Politics.

D.Health and Happiness.

名词解释