五年级的流水问题 一小时的量左右 不要太简单 急急急急急急急急急！
设船在静水速度为 X千米/小时
所以可知
4X+2x4=5X-2x5
可解得
X=18
所以 船在静水中的速度为18千米/小时
看在大叔这么用心的给你打这么多字的份上
把分给大叔吧。。。
选一选吧
1Fine for Parking
Tell me again," asked the judge, "why you parked there?" The driver rose and answered respectfully(尊敬地), "Because, Your Honor, it said 'Fine for Parking'" (note: "fine" has two meanings 1) good 2) pay some money for doing something wrong.
2.Self-help
I went into a bookstore the other day and asked the woman behind the counter where the self-help section was. She said, "If I told you, that would defeat the whole purpose." (note: "self-help" has two meanings 1) you take without paying 2) you can choose as you like)
3.I Couldn't Digest So Many Apples
Doctor gravely(严肃地): "If you want to enjoy a long life, each time you feel like a drink. Eat an apple instead." Patient: "Sorry, I couldn't digest(消化） so many apples."
4.Is This a Question
A college student in a philosophy class was taking his first examination. On the paper there was a single line which simply said: "Is this a question? " A student wrote: "If that is a question, then this is an answer." The students received an "A" on the exam.
5.A Dollar Per Point
A professor was giving a big test one day to his students. He handed out all of the tests and went back to his desk to wait. Once the test was over, the students all handed the tests back in. The professor noticed that one of the students had attached a $100 bill to his test with a note saying, "A dollar per point." The next class the professor handed the tests back out. This student got back his test and $64 change.
如果不好可登陆http://www.poptool.net/life/joke/127/story_5073.html
甲乙两码头相距150km，水流速度为3km/时，已知某船从甲码头逆流而上到乙码头又返回，返回时所有的时间等于去时的3/4，求船在水在静水中的速度。
(1)小芳在一条水流速度是0.01m/s的河中游泳，她在静水中的游泳速度是0.39m/s，而出发点与河边一艘固定小艇间的距离是60m，求她从出发点到小艇来回一趟所需的时间。
（2）志勇是小芳的邻居，也喜欢在该河中游泳，他记得有一次出发点与柳树间来回游一趟大约用了2.5min。假设当时水流的速度是0.015m/s，而志勇在静水中的游泳速度是0.585m/s，那么出发点与柳树间的距离大约是多少？
客轮和货轮从甲乙两港同时相向开出，6小时后客轮在离两港中点6千米处与货轮相遇。已知：客轮在静水中的速度是30km/h，货轮在静水中的速度是24km/h。求水流速度？
一只轮船从甲地开往乙地顺水而行，每小时行28千米，到乙地后，又逆水而行回到甲地，逆水比顺水多行2小时，已知水速每小时4千米。求甲、乙两地相距多少千米？
逆水行船4.5小时行72千米，已知水流速度是每小时3千米，这船顺水行相距165千米的路程需多少小时？
