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The first grade mathematical equation is applied quickly! ! ! ! ! If the details are correct, you will get extra points! ! (10)
1. Both Party A and Party B go to the second place, which is 251/2km apart. Party A rides a bike and Party B walks. Party A's speed is 2 kilometers faster than Party B's. After arriving at Party B first, Party A will return immediately and meet Party B on the way. At this time, the departure time from them is 3 hours. Ask for the speed of these two people.

Solution: Let speed b be x and speed a be 2X+2.

3(X+2X+2)=25.5*2

X=5

2X+2= 12

Party A and Party B run on a 400-meter-long circular track. The speed of Party A is 360m/min, and that of Party B is 240m/min.

The two men ran in the same direction at the same time. How many laps did they run together when they first met?

The two men ran in the same direction at the same time. How many seconds did they first meet?

Run 360-240 at the first meeting =120.

(360+240)*400/ 120=2000

2000/400=5 (circle)

The two men ran in the same direction at the same time. How many seconds did they first meet?

400/(360+240)=2/3 points

3. A passenger train conductor190m, a freight train conductor 290m, and the speed ratio of passenger and freight vehicles is 5:3. It is known that when driving in the same direction, the crossing time of two cars is 45 seconds. What is the speed of the bus per minute?

Assume that the speed of the bus is 5X and the speed of the train is 3X.

190+290=480

480/(5X-3X)=45/60

X=320

5X= 1600

4. An agricultural tractor plowed a third of the total area of more than 2 mu on the first day, and the remaining half 1 mu on the second day. At this time, there are 38 acres left. This land is * * *? The 12th letter of the Greek alphabet.

(2X/3-2)/2- 1=38

X= 120