30 points for asking the math master to come to the problem with the help

The age of the brother is x, and the age of the year is y

Then the younger brother is 55-x, and the younger brother is in the year: y 2

So there is. The age of the elder brother in that year is the age of the younger brother this year, y=55-x (1) The difference between the elder brother this year and that year is x-y years, and the younger brother is 55-x this year, and the age of that year is half of the elder brother at that time y 2, and the age difference is 55-x-y 2, and the age difference is equal, and there is the following formula.

x-y=55-x-y/2 (2)

Substituting (1) into (2) gives x-55+x=55-x-55 2+x 2x=33, then the younger brother is 55-33=22

Now let's see if you can understand.

Let the elder brother be x and the younger brother y

then we get the binary linear equation:

x+y=55………1）

y=2[y-（x-y）]…2）

Substituting (1) into x=55-y and substituting (2) to obtain y=22, then x=55-22=33

The elder brother is 33 years old and the younger brother is 22 years old.

Brother: 33 years old.

Younger brother: 22 years old.

It's also called a problem.

Process: Set the elder brother to be x years old and the younger brother to be y years old.

Age and: x+y 55 ......（1）

Age difference: x-y

then there is x (x-y) 2[y-(x-y)].

Simplification: x 2 3y

Bring in (1) x 33

y 22 arithmetic method:

Younger brother: 55 5 2 22 (years old).

Brother: 55 22 33 (years old).

Line Segment Diagram: Brother: A A

Brother: 2a a

I beg your pardon for the bad drawing.

Upstairs, I was a little surprised.

He called the master, not to say that it was a difficult problem.

I don't know the process, it should be done purely imaginarily.

Set: elder brother x years old, younger brother y years old.

x+y=55

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

Solving the above system of equations gives us x 33 y 22

178-105=73 tents that can be produced in one day by 1 garment production line and 1 children's clothing production line.

105-73=32 tents that can be produced in one day by 1 children's clothing production line73-32=41 tents that can be produced in one day by 1 garment production line 4x41+32x5=164+160=324 tents that can be produced in one day by all production lines.

324x3=972<1000

It's not done! Work overtime!

(1) Each garment production line produces an average of 41 tents per day, and each children's clothing production line produces an average of 32 tents per day.

2) Only 972 tents can be produced in three days, which cannot be completed. If I were the factory manager, I would have to give the workers a subsidy and encourage them to work overtime. Ensure that the task is completed smoothly or even exceeded.

Garment production line 105 (178-105)=41 per children's clothing line (105-41) 2=32

4*41+5*32=322 322*3=971 971 less than 1000 can not recruit workers to increase the production line.

1.After the conversion, each garment production line will produce tents x tops per day, and each children's clothing production line will produce tents y tops on average per day.

x+2*y=105

2*x+3*y=178

x=41 y=32

2. (4 * 41 + 5 * 32) * 3 = 972<1000 If you can't complete the task, how to reflect your sense of social responsibility depends on your character.

Answer: Harvesting 1 square meter of rice consumes liters of oil.

1 hectare = 10,000 square meters. Fuel consumption per square meter is:

The -4th power of the liter result is reserved to one decimal place.

1 hectare is equal to 10,000 square meters, and then use the result to keep one decimal place, it doesn't seem to work, hey, it can be converted into milliliters.

1 hectare = 10,000 square meters, the result is preserved to one decimal place).

2502523 15

Application Divide 52 = 260km

Except (1-3 8) = 640 copies.

Divide (60%-40%) = 400 meters.

Multiply 3 + 7000 = 7945 yuan.

4500=【

3]km[250 ]m

1 ton 50 kg = [ton.

Hour [ ] minutes = kilograms (incorrect) hours = minutes.

Hours = [3] hours [15] minutes.

7600 kg = [ ] tons [ ] kg = [ square kilometer (wrong)

6700 meters = [ 6] kilometers meters = [ kilometers .

300 cubic centimeters = [cubic decimeters] = [ ] liters.

2030 kg = [ ] tons = [2 ] tons of kilograms.

Kilometer = [1] kilometer [750] meter.

Square meter = [9000] square centimeter.

Application questions (1-80%) = 260 km (1-3 8) = 400 5 8 = 640 books.

(60%-40%)=80 meters.

7000 yuan.

(1); 3; 250; ;252; 3; 15; 7; 600;The square kilometer is wrong, and it cannot be converted. 6； 700； ；3； 3； ;2; 30; 1; 750; 9000.

Application Question 152 (1-80%) = 260 km2400 (1-3 8) = 640 Ben 3

Is the first one rice?

I really don't understand it, maybe it's 3 3

7 600 I don't understand, maybe it's tons.

Application *52=260km

(1-3 8) = 640 copies.

20%=400m

3*RMB.

250 This question is incorrect.

52 (1-80%) = 260 km.

400 (1-3 8) = 640 copies.

80 (60%-40%) = 400 meters.

7000*(1+3*RMB.)

4500=【 】km

3 ]km[ 250 ]m

1 ton 50 kg = [ton.

Hour [ ] minutes = kilograms Different units [ 3 ] kilograms [ 50 ] grams = kilograms.

3 ] time [ 3 ] minutes = hours.

Hours = [252] minutes.

Hours = [3] hours [15] minutes.

7600 kg = [7] tons [600] kg = [ square kilometer.

6700 meters = [6] kilometers [700] meters = [ ] kilometers.

300 cubic centimeters = [cubic decimeters] = [ ] liters.

2030 kg = [ ] tons = [ 2 ] tons [ 30 ] kg.

Kilometer = [1] kilometer [750] meter.

Square meter = [9000] square centimeter.

52 (1-80%) = 260 km.

400 (1-3 8) = 640 copies.

80 (60%-40%) = 400 meters.

7000x(1+ RMB.)

4500=【 】km

3 ]km[ 250 ]m

1 ton 50 kg = [ton.

3 ] kilograms [ 50 ] grams = kilograms???

Hours = [252] minutes.

Hours = [3] hours [15] minutes.

7600 kg = [7] tons [600] kg = [7600000] grams.

6700 meters = [6] kilometers [700] meters = [ ] kilometers.

300 cubic centimeters = [cubic decimeters] = [ ] liters.

2030 kg = [ ] tons = [ 2 ] tons [ 30 ] kg.

Kilometer = [1] kilometer [750] meter.

Square meter = [9000] square centimeter.

Application Question 1A bus travels 80% of the way from A to B, 52 kilometers away from B. How many kilometers are A and B apart?

2.There are 400 science and technology books in the library, which is 3 8 fewer than story books, how many story books are there?

3.To build a road, Team A repaired 60% of the total length, and Team B repaired 40% of the total length. It is known that Team A repairs 80 meters more than Team B, how many meters is the total length of this road?

4.Aunt Liu deposited 7,000 yuan in the bank for a period of 3 years, with an annual interest rate, how much money can Aunt Liu get when it expires? 【No interest tax for the time being】7000* in the first year (1+.)

7315 * in the second year (1 + approx. equals.)

The third year is about the same as the last to get.

Is this putting all the homework on the table? If you look at the textbook and sample questions, you can probably have them in the book.

Now elementary school students are all bad learners. Whoever teaches you these topics is harming you.

Roll a square sheet of paper with a side length of 50 cm into a cylinder as large as possible.

1) What is its underside circumference? (

Its underside circumference = side length of the square = 50 cm.

2) What is its height? (

Its height = the length of the sides of the square = 50 cm.

3) What is its side area? (

Its side area = the area of the square = 50 50 = 2500 square centimeters.

Hello, when you consider the problem of rolling a square paper with a side length of 50 cm into a cylinder as large as possible, when the two sides of the square paper are connected end to end, the cylinder that appears is the largest.

1) At this time, the circumference of the bottom surface of the cylinder is one side of the square, so the circumference of the bottom surface of the cylinder is 50cm.

2) The height of the circle is 50cm on the side of the square. (3) The formula for the side area is the circumference of the bottom surface multiplied by the height, so the side area of 50x50 is equal to 2500 square centimeters.

(1) The circumference is 50cm, according to a side roll, roll a circle, then the bottom edge of the circumference is just the side length of the square.

2) The height is 50cm

3) The side area is 50 50 = 2500 square centimeters.

3.(1).Its base circumference is 50cm;

2).Its height is 50cm;

3).Its side area is:

50*50=2500（cm^2）。

According to the question, it can be concluded that:

1. Bottom circumference: 50cm

2. Height: 50cm

3. The side area s=2 rh=2 x 25 x 50=2500 square centimeters The radius is through the bottom perimeter c = 2 r = 50

This gives r=25

(1), bottom circumference: 50cm

2. Height: 50cm

Measured area: 50x50=2500cm2

(1) The circumference of the bottom surface is 50

2) The height is also 50

3) Base area multiplied by height.