The solution of an equation and a problem 1000 pieces of cloth are distributed to 1000 officers and soldiers, 4 for each officer and 1 for each soldier. How many officers and soldiers are there? A rope around the tree, around three times, the rope more than 4 feet. Around four times, the rope less than 3 feet. How long is the rope?

The solution of an equation and a problem 1000 pieces of cloth are distributed to 1000 officers and soldiers, 4 for each officer and 1 for each soldier. How many officers and soldiers are there? A rope around the tree, around three times, the rope more than 4 feet. Around four times, the rope less than 3 feet. How long is the rope?

1： X = 4 + 3 = 7
2： The problem consists of X officers and Y soldiers
4X+Y/4=1000
X+Y=1000
Solving the equations: x = 200, y = 800
3： Let X be the circumference of the tree and y be the length of the rope
3X+4=Y
4X-3=Y
The solution of the equations is: x = 7, y = 25

One is to use the equation to write the solution and the equivalent relation, the other is the arithmetic solution
(you can write as many as you can, but you can't write blindly. Thank you for your cooperation.) write the subtitle clearly. It's better to have both of the above.)
1. The number of people in workshop a is 4 / 5 of that in team B. If 70 people are transferred from workshop B to workshop a, then the number of people in workshop B is 2 / 3 of that in workshop A. how many people are there in the two workshops?
2. Party A and Party B dig a canal from both ends at the same time, and meet at 15 meters from the midpoint. We know that Party B digs 40% of the total length, and how many meters did party a dig?
3. Party A and Party B work together to make a batch of parts, which is planned to be finished in 6 hours. Now Party B will work for 1.5 hours first, and Party A will join in the cooperation. It takes 3 / 5 hours more to complete the task than planned. It is known that party a makes 54 parts per hour. How many parts are there in this batch?
4. For a book, if you read 1 / 4 of the whole book on the first day, if you read another 18 pages, then the ratio between what you have read and the rest is 2:1?

27 / 25-4 / 5 = 7 / 25
70 / 7 * 25 = 250 (people) (counting the number of people in workshop b)
250 * 4 / 5 = 200 (people) (count the number of people in workshop a)
If workshop a has x employees, workshop B has 5 / 4x employees
（x+70）：（5/4x-70）=3:2
The solution is x = 200
∴5/4x=250
A: there were 200 and 250 people in each workshop
(2) 15 / (50% - 40%) = 150 (m) (total length)
150 × (100% - 40%) = 90 meters
If team a digs XM, team B digs 2 / 3xm
x-2/3x=30
The solution is x = 90
A: team a dug 90 meters
(3) Suppose B's work efficiency is x hours per hour
6.6x+5.1×54=6（54+x）
The solution is x = 81
∴6.6x+5.1×54=810
A: there are 810 parts in this batch
(4) 2 / 3-1 / 4 = 5 / 12
18 △ 5 / 12 = 43.2 (pages)
Suppose the book has x pages
1/4x+18=2/3x
The solution is x = 43.2
A: the book has 43.2 pages

How to solve this equation? What is the idea of solving this equation?
(X-40)*(1-20%)/700=(X-40-48)*(1-20%)/600

The first step is to remove the denominator and multiply both sides of the equation by 4200;
Step 2: simplify the equation by dividing both sides by (1-20%)
De denominator:
(X-40)*(1-20%)6=(X-40-48)*(1-20%)7
(X-40)6=(X-40-48)7
6x-240=7x-616
x=376

The solution and thinking of (x + 2) * 2 * 4
（X+2）*2*4
8x + 16 = 72 ← what's the meaning of this step? Where did 8x, 16, 72 come from?
There are 136 color TV sets of a and B models in a shopping mall. On the National Day promotion, 2 / 5 of a model and 3 / 7 of B model are sold. A total of 57 sets are sold. How many sets of a model are sold?

Question 1: 72 I don't know where you came from. It's estimated that you didn't complete your question. If 8, it's 2 ^ 4
Question 2: because I don't like to use equations, I can only do it for you with the arithmetic method of primary school: 136 * 3 / 7 = 408 / 7,
408 / 7-57 = 9 / 7, 9 / 7 / (3 / 7 - 2 / 5) = 45, model a sold 45
Ask if you don't understand