Hypothetical solution application problem thanks, I didn t learn equations .

Solution: Suppose you buy all brown sugar, then yuan).

If you buy all the sugar, then yuan).

The price difference is 640-480 = 160 (yuan).

The actual price difference is 220 yuan.

So, 220-160 = 40 (yuan).

Yuan kg) 40 kg).

That is, a difference of 50 kg.

It is also known that a total of 200 kilograms.

So, (200+50) 2=125 (kg) 200-125=75 (kg).

Then you don't need an equation!

Suppose that brown sugar and white sugar are bought 100 kilograms each, then the white sugar costs 320 yuan, and the brown sugar costs 240 yuan. In this case, white sugar costs 80 yuan more than brown sugar.

In fact, it cost an extra 220 yuan, so the actual sugar bought is more than 100 kilograms.

Let's say you buy 1 kilogram of brown sugar less and 1 kilogram of white sugar more. Then white sugar costs yuan, and brown sugar costs yuan. White sugar is more yuan than brown sugar.

Then it can be seen that the purchase change of 1 kg produces the difference between the purchase amount of white sugar and brown sugar. In the case of 100 kg each, the difference is 80 yuan, and the actual difference is 220 yuan, and the difference between 220 80 140 yuan. 140, so on the basis of 100 kg each, it is in line with the actual situation to buy 25 kg more sugar.

So the actual white sugar is 125 kilograms, and the brown sugar is 75 kilograms.

。It's really troublesome...

Can't use equations?

White sugar is more expensive than brown sugar kg, and all of it is white sugar.

Yuan. Let's say it's all brown sugar.

Yuan. When using all the white sugar, the price is 640 - the difference is 220, and the rest should be the price of brown sugar 420 yuan, but it is found that it is less than when it is all brown sugar.

480-420 = 60 yuan.

Get 75 kilograms of brown sugar or white sugar, because for each kilogram difference, 75 kilograms are 60 yuan.

Substituting this answer into the original question, it was found that 75 kg of white sugar did not meet the requirements of the question, so it should be 75 kg of brown sugar.

In the same way, with all brown sugar**480 + price difference 220 = 700 should have been all white sugar** but 700-640 = 60 yuan more than the actual part is the number of brown sugar or white sugar, 60 price difference.

If you use the equation solution.

Let's say white sugar x kilograms, brown sugar y kilograms.

x+y=200，x=200-y

Find y=75

That is, 75 kilograms of brown sugar and 125 kilograms of white sugar.

All the white sugar is 640 yuan, and the white sugar is 640 yuan more than the brown sugar.

Now if it wants to become 220, then buy less sugar and buy Hongtang.

If you buy one kilogram of white pond less, you will use less than white sugar.

Answer: Hongtang 75

125 sugar.

Let brown sugar have x kilograms and white sugar have y kilograms.

x＋y＝200

3．2y-2．4x＝220 （1）

x＝200－y

Substitution (!) ) to find y 125

x＝75

1) If the average workload of the two groups of workers is equal for the month, what is the quota per person for the month?

Solution: Set the per capita quota for this month to be x.

1/4(4x+20)=1/5(6x-20)x+5=6/5-4

x=452) If the average workload of workers in Group A is 2 more than that of Group B, then what is the per capita quota for this month?

Solution: Set the per capita quota for this month to be x.

1/4(4x+20)-1/5(6x-20)=2x=35

3) If the average workload of the workers in Group A is 2 pieces less than that of Group B, then what is the per capita quota for this month?

Solution: Set the per capita quota for this month to be x.

1 5 (6x-20) -1 4 (4x+20) = 2, that is, the per capita quota for this month is 35 pieces.

Set the per capita quota for this month to x pieces. Then the workload of group A for this month is (4x+10) pieces, and the workload of group B is (6x-20). The solution is as follows:

1) 4x+10=6x-20, x=15 pieces (2) (4x+10)-(6x-20)=2, x=14 pieces (3) (6x-20)-(4x+10)=2, x=16 pieces.

If there are x workers at the processing table, then there are (56-x) workers at the processing stool.

2×10x=15×(56-x)

20x=840-15x

35x=840

x=24 So the workers who process the stool are: 56-24=32

Set x people to process desks, 56-x people to process square stools.

10x*2=（56-x）*15

x=2456-x=32

24 people process desks and 32 people process square stools.

If there are x people in the processing desk, then the processing square stool is (56-x) people, and the equation is listed according to the problem

10x/15*(56-x)=1/2

168-3x=4x

7x=168

x=2456-x=56-24=32

Answer: There are 24 people processing desks and 32 processing square stools.

The third paragraph is long.

16+1) (1+1)=17 2=m)).

The first paragraph is long. m) the second section is long m).

If the worker who sets up the processing table is x, then the worker who processes the stool will quarrel with the brother (56-x).

2×10x=15×(56-x)

20x=840-15x

35x=840

x=24 So the stool has 56-24=32

If there are x people in the rented processing desk, then the processing square stool is (56-x) people, and the equation is listed according to the problem

10x/15*(56-x)=1/2

168-3x=4x

7x=168

x=2456-x=56-24=32

Answer: There are 24 people processing desks, and 32 people processing Fang Youqiao stool Xi Mozhao.

Solution: If you buy x copies of the science and technology virtual rolling book, then you buy (138-x) copies of the story book.

then 5x+3(138-x)=540

2x=540-414

2x=126

x=63 then 63 science books bought 63 Lao Hui, story books bought 75 copies.

Set x people to process desks and block slips, and 56-x people to process square stools.

10x*2=（56-x）*15

x=2456-x=32

24 people process the desk leather, and 32 people process the square stool mold.

1. The driving time of A and B is: 2 3 (20-18) = 3 hours.

The length of the whole journey is l:l=(20+18) 3=114 km.

2. The original area of S1 is: S1 = 50 30 = 1500 square meters.

The area after expansion S2 is: S2 = 1500 + 3500 = 5000 square meters.

The width of the expanded parking lot is l=S2 (50+50)=5000 100=50 meters.

Assuming that 100 Hengchong limb people are all male students, 200 trees should be planted (100*2=), which is 90 more than the actual load (100*2-110=)90, divided by 2-1 3 for male and female tree planting

Suppose there are a total of x students.

x*7/12+15=(x+15)*3/5

x=360

2. Clever unknowns. Several quantities can be set as unknown in a worksheet, but which one is easier should be carefully considered. For example:

The ratio of the velocity of A and B is 3:2, and when finding the velocity of A and B, we can let the speed of A be a kilometer hour and B be b kilometers and hour, which is a system of binary linear equations; Or let the velocity of A be a kilometer-hour, then B is 2 3a kilometer-hour, so that although it is a one-dimensional equation, there are fractions; Or let A have a speed of 3a kilometers per hour and B a speed of 2a kilometers per hour.

It can be seen that the last one tries to be the best. Unknowns are set according to different topics.

3. List equations according to the equiquantity relationship.

4. Solve equations. At this time, we may encounter two unknowns, and we can only list one equation, we need to see if there are still implicit conditions, such as the number of people and the number of objects, all of which must be positive integers, which are implicit conditions, especially in inequality equations. There is also the need to test the root of fractional equations.

5. Write down the unit and answer. This step is often overlooked, but in fact, it is a reflection of whether you have read the question, whether you know what the question requires, and whether you have to stand for marks in the exam.

6. Practice diligently, practice makes perfect. Touching the analogy bypass, drawing inferences from one another.

The above is a person's experience, I hope it will be useful to you!

First of all, you need to read the question carefully and analyze the known and unknown quantities in the question.

Secondly, you also need to find the equivalence relationship in the question.

Third, you need to list the equations based on the analysis in the first two steps.

Hope it helps.