Junior high school engineering problem application question type solution to a one dimensional one t

Give me a question, I don't know how to answer it.

It takes 18 days for team A to complete a project alone, and 15 days for B to complete it alone.

1) How long does it take for the two teams to complete?

Solution: It takes x days for two teams to work together.

1/18x+1/15x=1

11/90x=1

x=90/11

2) After five days of cooperation between teams A and B, how many days will it take for the rest to be completed by A alone?

Solution: After five days of cooperation between teams A and B, the remaining part will be done by A alone, and it will take x days to complete 1 18*5+1 15*5+1 18x=111 18+1 18x=1

1/18x=1-11/18

1/18x=7/18

x=7(3)After A does it for five days, the rest is completed by the two teams, how many days does it take to complete the project?

Solution: After A does it for five days, the rest is completed by the two teams, and it takes x days to complete the project 1 18x+1 15(x-5)=1

1/18x+1/15x-1/3=1

11/90x-1/3=1

11/90x=1+1/3

x=120/11

(1) It takes x days to complete the dismantling cooperation (1 18 + 1 19) x=1, x=90 11 (2) The dismantling also takes x days to complete (1 18 + 1 15) * 5 + 1 18 x = 1 x=7 (3) The remaining part of the dismantling is completed in x days 1 18 * 5 + (1 18 + 1 15) x = 1 x = 65 11 5 + 65 11 = 10 and 10 11

1. It takes x days to complete.

1/18+1/15)*x=1

x=90/11

It takes 90-11 days to complete.

2. It takes x days to complete the remaining part of A alone.

1-（1/18+1/15）*5=x/18

x=7After five days of cooperation between A and B, the remaining part will be done by A alone in 7 days 3, and it will take x days to complete the project.

1/18*5+(1/18+1/15)*(x-5)=1x=120/11

It takes 120-11 days to complete the work.

1.Set x days to complete. The equation is (1 18 + 1 15) x = 1 x = 90 11

2.Set x days to complete. The equation is (1 18 + 1 15) * 5 + 1 18 * x = 1 x = 7

3.Set x days to complete. The equation is 1 18 *5 + (1 18 + 1 15) * x=1 x=120 11

The amount of work is 1, the daily workload of team A is 1 18, and the daily workload of team B is 1 15 (1) If the cooperation of two teams takes x days to complete, then (1 18 + 1 15) x = 1, solved, x = 90 11

2) If the remaining part is done by A alone and it takes x days to complete, then (1 18 + 1 15) (x + 5) = 1, x = 35 11

3) It takes a total of x days to complete this project, then 5 18 + (1 18 + 1 15) x = 1, x = 75 11

If x cubic meters are used for the table, then 5-x cubic meters are used for the table legs.

By the inscription 50x*4=300*(5-x).

200x=300(5-x)

2x=15-3x

5x=15x=3 so 3 cubic meters for the table and 2 cubic meters for the legs.

If x cubic meters are used for the table, then 5-x cubic meters are used for the table legs.

Solution: 50x*4=300*(5-x).

200x=300(5-x)

2x=15-3x

5x=15x=3 so 3 cubic meters for the table and 2 cubic meters for the legs.

Let's do this first, and then ask if you don't understand.

A company applies to the bank for a loan of 600,000 yuan for A and B, with an annual interest rate of 10,000 yuan. A loan is 14%, B loan is 12%, how much yuan does this company apply for A and B from the bank?

1. The square wire frame with a side length of 8cm is straightened and re-bent to make a rectangular wire dismantled frame, the length of the rectangular frame is more than the width of 4cm, if the width of the rectangular frame is x (cm), then its length can be expressed as () cm, according to the equivalence relationship (, can be listed equation ().

2. There are 21,000 chickens left after a chicken farm sells 25% of the chickens, how many chickens are there in this chicken farm? If there are x chickens in the chicken farm, please list the equation.

3. A and B two reservoirs have a total storage of 40 tons of water, if 4 tons of water is injected into the first pool, and 8 tons of water is drained in the oak and B pools, then the water storage of the two pools is equal, and how much water is stored in the two pools of A and B?

4. Cast a rectangular iron block with a length of 10 cm, a width of 8 cm, and a height of 5 cm into a cylinder with a diameter of 20 cm. The result retains 2 significant figures).

5. Mathematical problems: A farm has 108 hectares of forest farms and 54 hectares of pastures. If you want to cultivate a fruit tree, you need to convert part of the pasture into a forest farm, so that the pasture area only accounts for 20% of the forest area, so how many hectares of pasture area needs to be converted into a forest farm?

6. A total of 115 members of a school actively participated in fundraising activities. Some members of the group donated 10 yuan each, and the rest donated 4 yuan each.

1) If the total donation is 790 yuan, how many members will donate 10 yuan?

2) Is it possible that the total amount of donations will be 785 yuan? Why???

1) There are x people who excavate the soil, so there are (200-x) workers who transport the soil, according to the title: 800 + 3x-5 (200-x) = 0

Solution. x=25

Name) soil transport = 200-25 = 175

2) The distance between the two places is x kilometers, according to the title.

x-10)/40=(x+10)/80

Solution x=30

Kilometer. Note is time.

1.Excavator x and earthhauler Y

x+y=200

800+3x=5y

x=25y=175

The distance between the two places is x kilometers, and the sum of the ants in the furnace cavity in the speed of A and B is yx=2 3y+10

x=4/3y-10

2/3y=20

y=30x=30