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Four application problems in grade one of junior high school (solved by one-dimensional linear equation)
1. On a certain expressway, the distance between a car and b car is 108km. On a certain day, at 16 o'clock sharp, the A train and the B train respectively set off from Station A and bilibili at the same time, driving in opposite directions. When it is known that the speed of car A is 45km/h and the speed of car B is 36km/h, when will the two cars meet?

Let the meeting time be x.

X[45+36]= 108

X=4/3

4/3 hours = 1 hour 20 minutes

So we met at 17: 20.

2. The school library presents books to a class of math interest groups. If each child has five books, there are still three books. If each child has seven books, there are five books missing. How many children does the math interest group have? How many books are there?

There are x people

5X+3=7X-5

X=4

That is, * * * has four children and * * has books: 5*4+3=23.

3. Two shepherds A and B said to B, "Give me your sheep 1. My sheep are twice as many as yours." B replied, "Why don't you give me your sheep 1 so that the number of our sheep will be the same?" Ask two shepherds how many sheep each shepherd boy has.

Let b be x, then a is X+2.

X+2+ 1=2[X- 1]

X=5

That is, B has five animals and A has seven animals.

The number of people in the first workshop of the factory is four fifths (4/5) less than that in the second workshop by 30 people. If 10 people are transferred from the second workshop to the first workshop, then the number of people in the first workshop is three quarters (3/4) of the number of people in the second workshop. What is the original number of people in each workshop?

Suppose there are x people in the second workshop, then the first workshop has 4/5X-30.

4/5X 30+ 10 =[X- 10]* 3/4

X=250

That is, there are 250 people in the second workshop and 250*4/5-30= 170 people in the first workshop.

4. The annual output value of the school-run factory is 6.5438+0.5 million yuan. If every additional investment of 654.38+0.000 yuan can increase the output value of 250 yuan in one year, how many million yuan can the annual output value reach with an additional investment of 6.5438+0.5 million yuan?

Up to x million yuan

X- 15= 1 .5*250/ 100

X= 18 .75

That is, the output value reaches 18. 750,000 yuan