问题 解答题

某旅行社有客房120间,每间房的日租金为50元,每天都客满.旅行社装修后要提高租金,经市场调查,如果一间客房的日租金每增加5元,则客房每天出租后会减少6间,不考虑其他因素,旅社将每间客房将日租金提高到多少元时,客房日租金的总收入最高?比装修前日租金总收入增加多少元?

答案

设每间房的日租金提高x个5元,日租金总收入为y,则

y=(50+5x)(120-6x),

即y=-30(x-5)2+6750,

当x=5时,ymax=6750,即旅社将每间客房将日租金提高到75元时,客房日租金的总收入最高,

∴日租金总收入多6750-120×50=750(元).

阅读理解

阅读下面的短文,并做后面的题目,从A、B、C 3个选项中选出能回答所提问题或完成句子

的最佳答案。

     Every year there is a Spring Festival in China. Usually it is in January or February. It is the most important

festival in China. So before it comes, everyone has to prepare things. They buy pork, beef, chicken, fruits and

many other things. And they often make a special kind of food-"dumplings". It means "come together". On the

day before the festival, parents buy new clothes for their children. Children also buy presents for their parents.

On the Spring Festival Eve (除夕), all the family members come back to their hometown. This is a happy

moment. Some sing and dance, some play cards and others get the dinner ready. When they enjoy the meal,

they give each other the best wishes for the coming year. They all have a good time.

1. Which is the most important festival in China?  [ ]

A. The Mid Autumn Festival.

B.The Spring Festival.

C. Children's Day.

2. When is the Chinese Spring Festival usually celebrated? [ ]

A. In March or April.

B. In May or June.

C. In January or February.

3.           is the special kind of food for the Spring Festival in China. [ ]

A. Chicken

B. Dumpling

C. Fish

4. What's the meaning of the food "dumplings" for Chinese people in the Spring Festival? [ ]

A. Look up.

B. Help yourself.

C. Come together.

5. The family           when they are having dinner together on the Spring Festival Eve.[ ]

A. give each other the best wishes

B. buy each other presents

C. sing, dance and play cards

选择题