题干

某工地调来144人参加挖土和运土,已知3人挖出的土1人恰好能全部运走.怎样调配劳动力才能使挖出来的土及时运走且不窝工(停工等待).为解决此问题,可设派x人挖土,其他人运土.列方程为:① 144
x
x
=
1
3
;②144-x=
x
3
;③x+3x=144;
144
x
x
=3.上述所列方程中,正确的有(   )

A:1个

B:2个

C:3个

D:4个

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答案(点此获取答案解析)

C

同类题4

请先阅读下面短文,掌握其大意,然后从各小题所给的A、B、C、D四个选项中选出可以填入相应空白处的最佳选项。

    When I was a junior high school student in 1980, God gave me a gift, and it was happiness.

    One weekend, I went to visit my grandparents in the countryside. On my way home a car ran over me and broke off my1because of its high speed.

    Several days later when I woke up at the hospital, I realized(意识) I had to spend the rest of my life2arms. How sad I felt at that time! I was full of fears.3slowly I knew I had to face the fact and got over it. I couldn't get my arms back even though I4 every day.

    5, it's easier said than done.6took me nearly half a year to get out of the sadness completely. I got so much from my past story. From then on, I could treat(对待)my life with a7mind. But in our daily life, I often see my classmates8about little things: They get a bad grade on a test; their bus comes9; they don't have a mobile phone but10do, and so on. But I only11life. I was lucky to realize from an accident that it is a waste(浪费) of our life to focus on(集中注意力)12you have lost. We13always think of what we have. So why are so many people unhappy? Someone may say, “My whole life would improve14I have a new car.” But when you get the car what happens? For a whole week you are walking on air. Then you go right back to being unhappy.

    Happiness depends on what we have! It's in our heart. It's a state of mind, even though you own the whole world, you may still feel15. Happiness comes from mastering the art of appreciating(感激) and taking pleasure in what you really have.