Reward of 40 points for urgent math problems using unary equations or equations .

Let the water increase rate be x per minute

Then the working efficiency of the pumping machine = (1+60x) 60=(1+20x) 20 2 then x=1 60

Efficiency = (1 + 60x) 60 = 1 30

With three pumping machines, the time is 1 (1 30 * 3-1 60) = 12 (minutes) and the wage of setting A is Y Yuan per week.

then B's wages =

Solution x = then B's wages =

Let the speed of the train be z meters and seconds.

Then the length of the body = (z-1) * 22 = (z-3) * 26z = 14, so the length of the body = (14-1) * 22 = 286 (meters).

Finding a condition and using an x (unknown) to represent another unknown is equivalent to representing the y of a 2-element equation with x...

Hope you can make it yourself!

Solution: Set the original water v, water inlet v1 per minute, each unit can pump water v2 per minute, and the time required for three simultaneous pumping is t

then the system of equations = 60 is listed by the title

Shift: v+60v1=60v2

v+20v2=20v2 ②

One minus two. Get v2=2vi

v=60v1

Then list the equations by the problem.

v+t×v1=t×v2

Substituting the relation gives t=12

That is, the time is twelve minutes.

Solution: If there are x large sofas that can seat 6 people, then there are (10-x) small sofas.

6x+4(10-x)=46

6x+40-4x=46

2x=6x=310-x=10-3=7

A: There are 3 large sofas for 6 people and 7 small sofas for 4 people.

Solve the X row for 6 people and the 10-x row for 4 people.

6x+4（10-x）=46

x=310-3=7 (row).

I'm still quite interested in the topic of junior high school, and I'm glad to serve you!

1.There is a train that has to cross at a speed of 600 meters per minute.

One or two iron bridges, the second iron bridge is 5 seconds longer than the first iron bridge, and the length of the second iron bridge is 50 meters shorter than twice that of the first iron bridge, try to find the length of each iron bridge.

600 m min = 10 m sec.

Let the length of the first bridge x, (2x-50) 10-x 10=5, and obtain x=100

So the first one is 100 meters and the second one is 150 meters.

2.An airplane flying between two cities with a wind speed of 24 km takes 2 hours and 50 minutes downwind and headwind.

The trip takes 3 hours and the flight distance between the two cities is ( ) km.

Set the speed of the aircraft x

17 6 (x+24) = 3 (x-24) multiplied by 6 on both sides

17（x+24）=18(x-24)

17x+24*17=18x-24*18

18x-17x=24*17+24*18

x=24*35

x=840 distance (840-24)x3=816x3=2448 km.

3.On the 400-meter circular track, A practices cycling at a speed of 6 meters and B runs at a speed of 4 meters.

1) If two people are walking with their backs to the ground at the same time 2) If A is 100 meters in front of B, both of them are walking in the same direction at the same time.

3) If B is 100 meters in front of A, the two of them are walking in the same direction at the same time.

1)400=6x+4x

2)6x-4x=400-100

3)6x-4x=100

4.A city holds a bicycle race, and the fastest person meets the slowest person after the start 45 minutes, and the speed of the slowest person is known.

It is xkm h, which is the speed of the fastest person 5 7, and the circumambulation of the city is 6km, so it can be seen that the speed of the slowest person is ( ).

45min=

7x*x=20

5.From A to B, go down the mountain first and then walk on a flat road, and someone rides a bicycle from A to B and goes down the mountain at a speed of 12km.

At a speed of 9 km, you can pass through the flat road and get to B in 55 minutes. When he returned, he passed through the flat road at a speed of 8 km, and went up the mountain at a speed of 4 km, and returned to A in an hour, finding the distance between A and B.

Set up a hillside xkm

then the flat distance is (55 60-x 12)*9

So (55 60-x 12)*9 8+x 4=

It is obtained that x=3, distance between A and B=3+(55 60-3 12)*9=9km

1 If the first bridge is x meters long, then the second bridge is 2x-50 long and the speed is 600 60 = 10 m seconds.

2x-50）/10-x/10=5

2 distance x km 2 hours and 50 minutes is converted to 17 6 hours 6x 17-x 3 = 24*2

3 1）x=400/（6+4） 2）x=（400-100）/（6-4） 3）x=100/（6-4）

4 6/（7/5x-x）45/60

5 Flat x km then Mountain 4( Full x+4(4(

1: The first iron bridge is 2x-50 meters long. And the speed of the car is 10 meters per second, get:

2x-50) 10 minus x 10=5 gives the value of x = 100, so the first iron bridge is 100 meters long and the second iron bridge is 150 meters long.

2: Let the speed of the aircraft be x kilometers per hour, x+24) 2 and 5 6=(x-24) 3 to get the value of x = 840

3: 1) If two people are facing away at the same time: let x seconds go before each other for the first time, (6+4) x=400

2) If A is 100 meters in front of B, and the two of them are walking in the same direction at the same time: let x seconds meet for the first time, (6-4) x = 400-100

3) If B is 100 meters in front of A and the two are traveling in the same direction at the same time: let x seconds meet for the first time, (6-4) x = 100

4: The speed of the slowest person known is xkm h, which is 5 7 of the speed of the fastest person, so the speed of the fastest person is 7 5xkm h, (7 5xkm h-xkm h) 3 4h = 6km The value of x = 20km h

5: The length of the slope road is xkm, and the length of the flat road is ykm. ①x/12+y/9=11/12 ②：y/8+x/4=

The sum of equations is a system of binary linear equations,,, you can first eliminate a letter, and then get the values of x and y, and then get the distance between A and B = x + y = 9 (kilometers).

Support the original!

1. Solution: The length of the first bridge is x meters, then the length of the second bridge is (2x-50) meters, and the meaning of the title is (2x-50) 600-x 600=5

Solution: x=3050

2x-50=6050

1. Let the length of the first bridge be x, so the length of the second bridge is 2x-50, the difference between the length of the two bridges is x-50, and the speed of the train is 10 meters per second, because the length of crossing the second bridge is 5 seconds longer than the first, so there is.

x-50 = 10 * 5 = 50, solve x = 100 meters, and the length of the second bridge is 2x-50 = 150 meters.

2. Set the flying speed of the aircraft to x kilometers per hour, there is.

x+24)*17 6=(x-24)*3, and x=840 km/h.

3. Let's say they meet after x seconds, 1) 6x+4x=400

2）6x-400=4x

3）6x=100+4x

4. The fastest human speed is 7x 5 km/h, x*3 4+6=7x 5*(3 4) solves x=20

5. Set the time to go down the mountain for x hours, then the length of the descent is 12*x, the time to go through the flat road is 11 12-x hours, find the length of the flat road is 9*(11 12-x)km, and then find out the time spent on the flat road when he comes back is [9*(11 12-x)] 8 hours, the time spent on the mountain is hours, and the length of the road up the mountain can be found to be 4* from the time of going up the mountain (because the road up the mountain and the road passing down the mountain are the same, so 12*x=4*(solve x=1). 4 hours, then the distance of A and B is 12 * (1 4) + 9 * (11 12-1 4) = 9km.

If the result is right, you should give points.

Forget it, I just found out that you're a dollar at a time...

1: Set the first iron bridge x meters long, and the second iron bridge (2x-50) meters.

x/10=(2x-50)/10+5

1) Design. If the mass of the B sugar is x, then the mass of the A sugar is 4x.

4x-100): Zheng next to or (x+100) = 7:5 i.e. 5（4x-100）=7（x+100）

2) The ratio of the number of students in the first grade to the second grade is 4:3, ie.

The ratio of the number of students in the second grade to the third grade is 2:3, ie.

So. The ratio of the number of students in the first grade to the second grade to the third grade is:

Establish. 8x for first graders, 6x for second graders, and 9x for third graders.

8x+6x-9x=300

The solution. x=60

So. 8x+6x+9x=23x=1380

There are 5x gold medals and 6x silver medals.

Rule. 15x+6x=42

The solution. x=2

So. There are 10 gold medals, 12 silver medals and 15 bronze medals.

1. 24

The second question. A walks 40 percent and B walks a third of the way.

Well, it's easy to say, so when A is gone, what fraction of a day is B?

Uh-huh (1 3) (40%) = 5 6en en How many more haven't gone?

en en 1-5/6 = 1/6

That's a sixth of 40 km.

1. Workshop 1: Workshop 2 is = 3:2

So, the second workshop is 200 (3-2) 2=400 (people), and the first workshop is 400 2 3=600 (people).

The three workshops account for 1 3 of the whole factory, so.

The first and second workshops account for 1-1 3=2 3 of the whole plant

Therefore, the number of people in the whole factory is (400+600) (1-1 3)=1500 (people) 2, and the ratio of morning, middle and night shifts is written in the form of a continuous comparison

Early: Medium = 2:3 = 8:12

Medium: Night = 4:5 = 12:15

Morning: Middle: Night = 8:12:15

So, early = 140 (8 + 12 + 15) 8 = 32 (people) medium = 140 (8 + 12 + 15) 12 = 48 (people) night = 140 (8 + 12 + 15) 15 = 60 (people) 3, after adding 6 grams, the new alloy is 36 grams, so the original is 36-6 = 30 (grams) the copper in the original alloy is 30 (2 + 3) 2 = 12 (grams) the zinc in the original alloy is 30 (2 + 3) 3 = 18 (grams) now the copper in the alloy remains unchanged, Zinc is 18+6=24 (grams), so the copper-zinc ratio in the new alloy is.

Plant 1 is better than plant 2 = 3:2

One plant minus two plants = 200

There are 600 people in the first factory and 400 people in the second factory.

The total number of three factories = 1:3 = the ratio of three factories (three factories + 1000) is 500 people in three factories, and the total number is 1500

×（2＋3）÷2／3

2. Morning: 140 35 8

Medium: 140 35 12

Late: 140 35 15

Copper Zinc 12 24

Give it to me! It's a word-by-word type-out!

By the way, if you have anything to do in the future, you can ask me, and I can help you answer!

(1) 200 2 is equal to 400 3 divided by 2 is equal to 600 600 plus 400 plus 200 is equal to two-thirds of the total number of employees in the whole field, 1200 divided by 2 3 is equal to how many people there are.

2) 2 to 3 equals 8 to 12 4 to 5 equals 12 to 15 then 8 to 12 to 15 equals to the morning shift than the middle shift to the night shift 140 divided by (8 plus 12 plus 15) equals 4 4 is a portion 4 8 equals the morning shift 4 12 equals the middle shift 4 15 equals the night shift.

This is really simple ... Count yourself sincerely... If you don't do this, what are you going to do...

Original area: 15*18

Garden size: 15*18*2 3

Path area (total sector area): 15*18-15*18*2 3 Path width: (15*18-15*18*2 3) (15+18) As long as the width is not wider than the original.

The sector of each corner is the same, which is the radius of the area of a circle r 2 = (15*18-15*18*2 3) pi.

The diameter is smaller than the original width.

It's very simple to tell you on the spot, but it's not exhausting to death if you fight like this.

In addition, upstairs is not a bad eye, which needs a picture.