1. Two trains depart from two cities which are 8 10 kilometers apart, and meet each other 10 hour after departure; If the first train leaves 9 hours before the second train leaves, the second train meets 5 hours after the departure. What is the speed of each train?

Suppose the speed of one train is x km/h and the other is y km/h, according to the meaning of the question:

(X+y)× 10=8 10

9x+(x+y)×5=8 10

X+y=8 1

X=8 1-y

14x+5y=8 10

14×(8 1-y)+5y = 8 10

1 134- 14y+5y = 8 10

1 134-9y=8 10

Y=36

X=45

A: The speed of these two trains is 36 kilometers and 45 kilometers per hour respectively.

2. A worker receives the task of processing a batch of parts and completes it within a limited time. He plans to make 10 parts per hour, which will exceed the task by 3 parts. If he makes 1 1 parts per hour, he will finish it 1 hour in advance. How many parts has he machined? How many hours is the deadline?

If the time limit is x hours, the number of parts is 10x-3.

10x-3 = 1 1(x- 1)

10x-3 = 1 1x- 1 1

X=8

10x-3=80-3=77

A: There are 77 parts to be processed, and the deadline is 8 hours.

4. Party A and Party B go the same way. Party A travels 3 kilometers per hour and Party B travels 5 kilometers per hour. Party a passes through place a at noon 12, and party b passes through place a at 2 pm. What time does Party B catch up with Party A in the afternoon?

Let's meet at x in the afternoon, and then:

2×3=(x-2)(5-3)

X=5

A: Catch up with A at 5 pm.

5. A said to B, "I am twice as old as you are now; When you reach my present age, we will be 63 years old. " Ask him how old they are now.

Let a's age be x and b's age be y, then:

X=2[y-(x-y)]

X+(x-y)+y+(x-y)=63

X=4y-2x

3x=4y

3x-y=63

Y=3x-63

3x=4(3x-63)

x=4x-84

3x=84

X=28

Y=3x-63=3×28-63=2 1

A: A's age is 28, and B's age is 2 1.

3. There are three turners. The labor efficiency ratio of A, B, C, A and B is 6:5, and the labor efficiency ratio of B and C is 3:4. They have 265,438+0,200 parts to process. How to assign tasks so that they can complete tasks at the same time?

6:5= 18: 15

3:4= 15:20

Let the efficiencies of A, B and C be 18x, 15x and 20x respectively. According to the meaning of the question:

18x+ 15x+20x = 2 1200

53x=2 1200

X=400

18x=7200

15x=6000

20x=8000

A: A, B and C can be configured with 7200, 6000 and 8000 respectively, which can be completed at the same time.