Sixth grade math problems need to be processed, and sixth grade math problems must have a process

1。A project, A alone does 10 days to complete, B alone does 15 days to complete, A first does 3 days, and the rest of the two work together, how many days does it take to complete? How many days did A work?

A 3 days to complete 1 10x3 = 3 10

The work efficiency of A and B and = 1 10 + 1 15 = 1 6 still need (1-3 10) (1 6) = 21 5 days.

A worked a total of 3 + 21 5 = 36 5 days.

2。A project, A alone does 10 days to complete, B alone does 15 days to complete, two people cooperate, A has something to do in the middle of the way to leave a few days, the whole project is completed in 12 days, A works for a few days?

B 12 days to complete 1 15x12 = 4 5

A completes 1-4 5 = 1 5

A worked (1 5) (1 0) = 2 days.

3。A can complete a job for 6 hours, B then 12 hours, A for 8 hours, B for 6 hours, if A does 3 hours and B then does it, how many hours will it take to complete?

The first time: A and B cooperate for 6 hours, and B does it alone for 6 hours.

The second time: A and B cooperate for 6 hours, and A does 8-6 = 2 hours to complete.

A does as much as B does in 2 hours and B does 6 hours, which means that B completes 3 times as long as A.

Therefore, B does it in 12 hours, and A completes it in 4 hours, and it takes 4+6=10 hours to complete this project.

B takes 10x3=30 hours.

A does 3 hours to complete 1 10 3 = 3 10

B also needs (1-3 10) (1 30) = 21 hours.

1.A completes one-tenth of a day to one-fifteenth of a day.

It still takes days, and A works for days.

2.A completes one-tenth of a day to one-fifteenth of a day.

Shejia left for x days.

x 15) + (12-x) * [1 10) + (1 15)] = 1x = 10 A worked for 2 days.

3.Let A complete A every hour and B complete B every hour

6a+12b=1

8a+6b=1

Get a = 1 10 and b = 1 30

A does it for 3 hours and B does it.

It will take another 21 hours.

1.(1-3 10) (1 10 + 1 15) = days) 3 + days).

2.(1-12 15) (1 10) = 2 (days).

3.A does 2 hours and B does 6 hours, all A does, 6 + 12 6 * 2 = 10 hours, now do 3 hours, A does another 10-3 = 7 hours to finish, equivalent B does 7 2 * 6 = 21 hours.

A leaves halfway, then B has been doing it, 1 15 * 12 = 4 5 A has been doing it for 2 days.

A first 6 hours, B then 12 hours, can be considered to be 6 hours of cooperation, then B to do 6 hours, A first 8 hours, B then 6 hours, can be considered to be 6 hours of cooperation, A then 2 hours, in this way, it can be concluded that A 2 hours and B 6 hours are the same. The time ratio is 1:3

6 hours of work A is equivalent to 12 hours of B, so the whole work of B takes 24 hours, B's efficiency is 1 24, and A's efficiency is 3 times that of him, that is, 1 8

5 8 (1 24) = 15 hours.

1, A's work efficiency is 1 10, B's work efficiency is 1 15, and the work efficiency of two people is (1 10 + 1 15) = 1 6

After three days of A, there is 1-3 10=7 10

It takes time (7 10) (1 6) = 21 5 So, it takes 4 and 1 5 days, and A works 7 and 1 5 days...

2, A's work efficiency is 1 10, B's work efficiency is 1 15, and the work efficiency of two people is (1 10 + 1 15) = 1 6

If two people work together for t days, then B works alone for (12-t) days, and you can get:

1 6) t + 1 15) (12-t) = 1 solution t = 2 So, A worked for 2 days...

3 Let the work efficiency of A and B be a and b respectively, according to the meaning of the topic:

6a+12b=1

8a+6b=1

The solution yields a=1 10 b=1 30

Therefore, after A does it for 3 hours, B still needs to do (1-3 10) (1 30) = 21 (days).

B still needs to do 21 days...

B 9 days to complete.

A is done. A worked. 2 5 1 10 4 days.

Team A was transferred halfway through.

9 4 5 days.

The Handsome Wolf Hunting team will answer for you:

There are two types of lidless trays.

Made of two squares and three rectangles, 100 cartons need 200 squares, obviously the squares are not enough;

If you use a square and 4 rectangles, you need 100 squares for 100 cartons, and you can't use up all the squares exactly.

Set up to make a kind of carton x, then make a kind of carton (100-x), 2x + (100-x) = 120, x = 20, 100-x = 80, 20 kinds of carton need to be rectangular: 3 20 = 60 sheets, kind of carton (100-20 = 80 pieces), need to be rectangular: 4 80 = 320 sheets, a total of 60 + 320 = 380 sheets of rectangle.

(1) A horizontal box needs 3 rectangles, 2 squares, and a vertical box needs 4 rectangles and 1 square.

Then: 4x+3y=320

x+2y=130

The solution yields x=50 and y=40

2) Set x vertical cartons and Y horizontal cartons. The system of equations x+y=a

4x+3y+x+2y=5x+5y=500

i.e. x+y=a=100

And since both cartons must be there, so x can be all integers from 1 to 99, so there are 99 schemes.

If it is made into a vertical type of x, then a horizontal type (100-x) pieces.

The equation is: x+(100-x)*2=120

The solution is x=80, that is, 80 vertical and 20 horizontal.

So you need rectangular cardboard: 80*4+20*3=380pcs.

(1).Primary: 2 1 < (180-60) 360>=2 3 Secondary: (2 3) 2=4 3

Three: 4 3

Four times: (2 3) 3=2

Bingyun [Zizhu], hello:

In a cuboid pool with a length of 3 meters, a width of 2 meters, and a height of 2 meters, put a cylinder with a bottom circumference of 314 square decimeters, and the water surface rises by 2 decimeters, what is the volume of this cylinder? (To process).

Water surface rise: 2 dmm.

Cylindrical volume: 3 2 cubic decimeters).

The circumference of the cylindrical container is centimeters, put in a conical plumb weight and submerge it completely, the water surface rises by 6 centimeters, what is the volume of the conical plumb weight? (To process).

Container radius: cm).

Weight volume: cubic centimeters).

A cylindrical glass jar with a base diameter of 20 cm. Take a cone with a base radius of 8 cm completely into the water, and the water surface rises by 3 cm, find the volume of this cone. (To process).

Radius of the cylinder: 20 2 10 (cm).

Cone volume: cubic centimeters).

Fill a cylindrical cup with a base radius of 10 cm and submerge it in a conical weight with a base radius of 5 cm. When the plumb weight is removed from the cup, the water level of the cup drops by 5 cm, how many centimeters is the plumb weight? (To process).

Weight volume: cubic centimeters).

The height of the plumb weight is: 1570 3 (cm).

What is the ratio of the mass to the volume of a piece of starch iron that weighs 546 grams in a cylindrical container with a base area of 20 square centimeters, and the water surface rises by centimeters? (To process).

Iron block volume: 20 cubic centimeters).

The ratio is: 546: 70 grams of cubic centimeters).

1. The title is wrong: "Put a cylinder with a bottom circumference of 314 square decimeters," how can the perimeter be "square decimeter"?

Moreover, this data is not used, the volume of the cylinder is: 3 2 cubic meters) 2, the radius of the cylindrical container: cm).

Conical weight volume: cubic centimeters).

3. The radius of the glass cylinder: 20 2 10 (cm).

Cone volume: cubic centimeters).

4. Plumb weight: cubic centimeters).

The plumb weight height is:1570 (cm).

5. Starch iron block volume: 20 cubic centimeters).

The ratio is: 546:70 grams cubic centimeters).

1. Water surface rise: 2 decimeters.

Cylindrical volume: 3 2 cubic decimeters).

2. Container radius: cm).

Weight volume: cubic centimeters).

3. The radius of the cylinder: 20 2 10 (cm).

Cone volume: cubic centimeters).

4. Plumb weight: cubic centimeters).

The height of the plumb weight is: 1570 3 (cm).

5. Iron volume: 20 cubic centimeters).

The ratio is: 546: 70 grams of cubic centimeters).

1.The volume of the cylinder is equal to the volume of the rising water v = cubic meter.

The meeting point is east of the flagpole 4m2 from the flagpole) Question about the question? One swallow and four finches are equal in mass Swallow = Finch Known Each sparrow is heavier than each swallow.

How can it be???

Solution: 1:1 4 2 9 9 8

102 8 17 48 (person) ......The number of people in the computer group is 102 9 17 54 (people) ......The number of people in the art group is 2: 1, 12, 1, 20, 1, 30

1 5 1 30 6 (days).

3:3 15 18 (day).

3 10 (1 12 1 15) 2 (day) ......The number of days of cooperation between A and B is 2 days) ......The total number of days B did it.

3 10 (1 6 1 10) days) ......The number of days that A does it alone.

The landlord seems to be lazy?

1: Set the art group x, the computer group y, then the title of 2x 9 = y 4 x + y = 102

The solution is x=54 y=48

Do the rest yourself

The number of people who subscribe to the "Mathematics Newspaper for Primary School Students": 3 4x40 = 30 (people).

Number of people who subscribe to "Chinese Learning for Primary School Students": 4 5x40 = 32 (people).

The number of people in both categories: 30 + 20-40 = 22 (people).

Suppose there are x people who only set the math newspaper, there are y people who only set the language newspaper, and there are z people who both set the math newspaper.

x+y+x=40

x+z=3/4*40

y+z=4/5*40

Simultaneous solution yields x=6 y=8 z=24, so there are at least 24 people who have both of them.

40*3 4=30 (person).

40*4 5=32 (person).

30 + 32 - 40 = 22 (people).

A: At least 22 people for both?

40 times 4/5 plus 40 times 3/4 minus 40 equals 22

According to the product of the inner term equal to the product of the outer term, it can be obtained:

1)4:x=:1

x=82)7:x=13:1

13x=7x=7/13

4:x= Divide both sides of the equation by 4 to get x=

7: x=13 Divide both sides of the equation by 7 at the same time to get x=13 7

1.This question should be: the fertilizer plant produced 300 tons of fertilizer in September, exceeding the plan by 60 tons, what percentage of the production in September?

Solution: 300 (300-60)=300 240=125%2This question should read:

Add 16 to the first term of 8:5, and to keep the ratio constant, add (10) to the last term because: 8:

5 = 24:15 Because 8 + 16 = 24 is actually 3 times larger than the previous term. Therefore, the latter item should also be expanded by a factor of three.

m = 160 cm, m = 120 cm. All are divisible by 20 centimeters, and there is no preference problem. (160 20) (120 20) = 8 6 = 48 (pcs).

5.There is a group with the 1st group stage, and there is a group with the 2nd group stage.

There is a group in Group 3 and 1 group in Group 4.

So there is a group with the 5th group stage, and therefore, the 5th group players played 2 games.