问题 解答题

某校准备组织290名学生进行野外考察活动,行李共有100件。学校计划租用甲、乙两种型号的汽车共8辆,经了解,甲种汽车每辆最多能载40人和10件行李,乙种汽车每辆最多能载30人和20件行李。

(1)设租用甲种汽车x辆,请你帮助学校设计所有可能的租车方案;

(2)如果甲、乙两种汽车每辆的租车费用分别为2000元和1800元,请你选择最省钱的一种租车方案。

答案

解:(1)设租用甲种汽车x辆,则租用乙种汽车(8-x)辆。

依题意得:   解得

方案①:当时,

方案②:当时,

 即:租用甲种汽车5辆,乙种汽车3辆或者租用甲种汽车6辆,乙种汽车2辆

(2)设总费用为W元,则

∵200>0   ∴W随着x的增大而增大。

∴x=5时,W最小值为15400元。

阅读理解

When I was small and my grandmother died, I couldn’t understand why I had no tears. But that night when my dad tried to cheer me up, my laugh turned into crying.

.   So it came as no surprise to learn that researchers believe crying and laughing come from the same part of the brain. Just as laughing has many health advantages, scientists are discovering that so, too, does crying.

Whatever it takes for us to reduce pressure is important to our emotional (情感的) health, and crying seems to study found that 85 percent of women and 73 percent of men report feeling better after crying.

Besides, tears attract help from other people. Researchers agree that when we cry, people around us become kinder and friendly and they are more ready to provide support and comfort. Tears also enable us to understand our emotions better; sometimes we don't even know we're very sad until we cry. We learn about our emotions through Crying, and then we can deal with them.

Just as crying can be healthy, not crying — holding back tears of anger, pain or suffering — can be bad for physical (身体的) health, Studies have shown that too much control of emotions can lead to high blood pressure, heart problems and some other illnesses. If you have a health problem, doctors will certainly not ask you to cry. But when you feel like crying, don't fight it. It's a natural — and healthy — emotional response (反应).

60. Why didn't the author cry when her grandmother died?

A. Because her father did not --ant her to feel too sad.

B. Because she did not love her grandmother.

C. Because she was too shy to cry at that time.

D. Tie author doesn’t give the explanation.

61, It can be inferred from the text that ______.

A. there are two ways to keep healthy

B. crying does more good to health than laughing

C. crying and laughing play the same roles

D. emotional health has a close relationship to physical health

62. According to the author, which of the following statements is true?

A. Crying is the best way to get help from others.

B. Fighting back tears may cause some health problems.

C. We will never know our deep feelings unless we cry.

D. We must cry if we want to reduce pressure.

63. What might be the most suitable title for the text?

A. Power of Tears         B. How to Keep Healthy

C. Why We Cry           D. A New Scientific Discovery

判断题