问题 单项选择题

小王从家开车上班,汽车行驶10分钟后发生了故障,小王从后备箱中取出自行车继续赶路。由于自行车的速度只有汽车速度的3/5,小王比预计时间晚了20分钟到达单位。如果之前汽车再多行驶6公里,他就能少迟到10分钟。问小王从家到单位的距离是多少公里()

A.12

B.14

C.15

D.16

答案

参考答案:D

解析:

由汽车和自行车的速度之比为3比5,设汽车、自行车的时速分别为3x公里/分钟、5x公里/分钟。汽车行驶6公里,自行车少耗时10分钟,则有=10,x=0.08。可以得出汽车的速度为0.4公里/分钟、自行车速度为0.24公里/分钟。设发生故障后,汽车的原预定时间为t分钟,则有0.4×10+0.24×(t-10+20)=t×0.4,t=40,则从家到单位的距离为s=0.4×40=16(公里)。

[华图名师点评] 此题难度较高,要求思维缜密且灵活。首先根据时间差可以求出汽车和自行车的速度,但是列出后面的第二个方程稍难,需要大家在平时的训练中加强列方程的能力。

阅读理解

根据短文内容,选择最佳答案。

     One day an Indian went to his doctor. The doctor looked him over and said, "Medicine ( 药)won't

  help you. You must have a good rest. Go to a quiet place for a month, go to bed early, drink milk, walk

  a lot, and smoke( 吸) only one cigar ( 烟) a day. "

     A month later the Indian came to see the doctor again.  "How are you?"said the doctor, "I'm glad to

 see you again. You look much younger. " "Oh, doctor, I feel quite well now!"said the Indian.  "I had a

  good rest. I went to bed early, I drank a lot of milk. I walked a lot . You certainly helped me. But you

 told me to smoke one cigar a day, and that one cigar a day almost killed (杀死) me at first. It was no joke

  to begin smoking at my age. "

1. One day an Indian _____.

    A. wasn't feeling well    

    B. went to see a friend    

    C. felt very tired  

    D. went to his doctor and helped him

2. His doctor _____.

    A. could not help him  

    B. was good to him    

    C. told him what to do  

    D.  was glad to see him

3. When the Indian came to see the doctor again _____.

    A. the Indian was younger    

    B. the doctor was not free    

    C. the Indian  felt quite well    

    D. the doctor looked him over

4. The Indian told the doctor _____.

    A. he liked doing all those things    

    B. he almost killed him    

    C. to smoke one cigar a day  

    D. one cigar a day was very difficult at the beginning

5. From this story we can guess _____.

    A. the Indian was not a young man    

    B. the doctor was very interesting   

    C. the doctor was a good one    

    D. the Indian didn't smoke at first

单项选择题 A型题