问题 填空题

某商品经过连续两次降价,销售单价由原来的125元降到80元,则平均每次降价的百分率为               .

答案

20%.

题目分析:解答此题利用的数量关系是:商品原来价格×(1-每次降价的百分率)2=现在价格,设出未知数,列方程解答即可.

试题解析:设这种商品平均每次降价的百分率为x,根据题意列方程得,

125(1-x)2=80,

解得x1=0.2=20%,x2=-1.8(不合题意,舍去);

故答案为:20%

考点: 一元二次方程的应用.

单项选择题
阅读理解

One would have to be a fool to overlook (忽视)the importance of using positive(积极的) thinking for you rather than allowing negative thinking to work against you. In recent years, research in psychopharmacology (精神药理学) has proved what many people have known over the centuries: a positive attitude is good for you, good for your health, good for your wealth, good for everything. Researchers found that a positive attitude produces a specific chemical reaction which makes people feel better, while negative thinking results in a decline of hormone (荷尔蒙) and shuts down the immune (免疫的) system. This leads to illness and depression. Positive thoughts will make you feel better. Even if you must begin by literally forcing yourself to be positive (faking it, so to speak), it will become contagious (会传播的) and the positive thoughts will generate nice little chemicals and good feelings which will reinforce the positive thoughts.

For example, if you force yourself to smile or laugh, even when you don't feel like smiling or laughing, if you keep at it for a few minutes, you will soon feel like it. Feelings can generate (导致)thoughts, but thoughts can also generate feelings. Control your thoughts and you can control your feelings. Positive thinking is important in all aspects of our lives. There is probably no single factor more important in determining your success in achieving your career objectives than your own attitude.

It's often been said that in the land of the blind, the one-eyed man is king. And in the office of militant (好战) negativism, the positive workers shine like gold. You cannot control external events, but you can learn to control your reaction to those events and thereby have a positive attitude and be happy. This vital key to success is totally within your control. Use it.

小题1:We can infer from the passage that         .

A.positive thinking can cure you of your diseases

B.positive thinking can easily be generated by anyone

C.a decline of hormone may cause you to be depressed

D.a specific chemical reaction is the cause of negative thinking小题2:According to the passage, which of the following is true?

A.Feeling and thoughts can generate each other.

B.It's easier to control thoughts than to control feelings.

C.Your success depends wholly on your attitude.

D.Keeping smiling will surely make you successful.小题3:Just like a one-eyed man in the land of the blind, you should             .

A.control your feeling to what is happening to you

B.be king in your office

C.pay no attention to what is going on around you

D.take positive attitude in the office of militant negativism小题4:The best title to the passage is             .

A.The Bad Effect of Negative Thinking

B.Why Should People Think

C.Thinking: The Vital Way

D.Positive Thinking Benefits People