Can you help me solve the math problems in junior high school? Application problems for unary equati

Set: x boys, 156-x girls.

x-1/11x=2(156-x-12）

x=99 57 girls.

There are x boys and 156-x girls in this grade.

x*(1-1/11)=(156-x-12)*2x*10/11=312-2x-24

x=99156-x=57

There are 99 boys and 57 girls.

Set up 156-x for boys x girls

x-x/11)=2*（156-x-12）

x = 99 girls = 156 - 99 = 57

So there are 99 boys.

There are 57 girls.

Let the boy be x and the girl 156-x;

x-1/11x=（156-x-12）×2

Solution: x = 99 boys.

156-99 = 57 girls.

Set up x boys.

10/11x=2(156-12-x)

Multiply 11 on both sides

10x=22(144-x)

10x=3168-22x

Add 22x at the same time

32x=3168

x=99 156-99=57 (person).

Set the number of girls to x

2（x-12）/（10/11）+x=15632x=1824

x=57 156-57=99

A: There are 99 boys and 57 girls.

Let the number of boys be x and the number of girls be y, then there is the equation:

1-1/11)x=2(y-12)

x+y=156

After repairing its 1 3 in 18 days, then repairing it every day 1 3 18 = 1 54 The original work efficiency is 1 54, the work efficiency is increased by the original 1 5, and the improved work efficiency is: 1 54 (1 + 1 5) = 1 45

The amount of work completed in 4 days is: 4 1 54 = 2 27 The amount of work completed to improve work efficiency is: 1 2-2 27 = 23 54 The time to improve work efficiency is half of the time

23 54 (1 45) = 115 6 days, and half of the time to complete it is 4 + 115 6 = 139 6 days.

Solution: Half of it can be repaired in x days.

From the meaning of the title:

4（1/3÷18）+[1/3÷18）×（1+1/5）]x=1/2x=139/6

A: ......That's how it should be.

Suppose the efficiency of the day is 1, the fifth day is 6 5, the length of the whole road is 3*18=54, and the half of the road is 27, assuming that it will take x more days.

Then 4*1+(6 5)*x=27

So 6x 5=23

x = so it takes another 20 days, which is a total of 24 days to complete half of it.

Solution: Let its work efficiency be x.

According to a road, a third of it can be repaired in 18 days.

Therefore, the efficiency of the total project is 18*3*x=54x.

So half of it is 54x 2=27x

So we can list the equation as:

4*x+6 5*x*time=27*x.

The left and right sides can be about x to go.

4 + 6 5 * time = 27

So time = approximately equal to Ha).

So we're going to have at least 20 days to finish half of it.

Solution, a total of x days to complete half of it, column equation ( 1 2 1 3 18 4) (x 4) (1 + 1 5) (1 3 18) solution x=139 6 A total of 139 6 can be completed half of it.

The original plan was 18 * 3 = 54 days to complete, then the original task was completed 1 54 per day, and the work efficiency was 1 45 per day after 4 days

Suppose half of the repair is done in x days, then.

4*(1 54)+(x-4)*(1 45)=1 2 There seems to be something wrong with the data, x is not an integer.

It takes 18 * 3 = 54 days to complete a road.

Half of the rest takes x days.

4/54)+(1/54)*(1+1/5)x=1/2

Set a total of x days to complete half of it.

1/54)×4+(1/45)×(x－4)=1/2x=139/6

Rounded up to 24 days.

Let the original work efficiency be 1, and it will take S days after four days of work.

4+xs=1/2x3x18

s plus 4 is the total number of days required to complete half of the repair.

Solution: Set up the work for 4 days and finish half of it in x days.

Because the planned speed is 1 18 * 1 3 = 1 54, after 4 days it is 1 54 * column equation: 1 45x = 1 2-4 54

x=115/6

So half of the time is 115 6 + 4 = 139 6 days.

Solution: Set X days to finish one-third of him.

4 1 54 + (1 54 1 5) x = 1 2 solution gets: x = 115

A: 115 days to finish one-third of it.

That's probably how it should be.

Set a total of x days to repair half of him.

4/54)+(1/54)*(1+1/5)x=1/2x=

So it takes another 20 days, which is a total of 24 days to complete half of it.

Solution: Half of it can be repaired in x days.

4/54+6/54x5 x=1/2

Note: To list.

The retail price is set at $x per kilogram.

1000x/[(

x x = retail price per kilogram.

The retail price is set at $x per kilogram.

1000x/[(

x/x=

Solution: Let the water flow velocity be x kilometers per hour.

5(x+12)=(5+50/60)(12-x)5x+60=35/6(12-x)

Divide both sides by 5 and multiply by 6 at the same time to get:

6(x+12)=7(12-x)

6x+72=84-7x

13x=12

x=12/13

A: ......

Let the water flow velocity be x; 50 minutes = 5 6 hours.

x+12km)x5=(12km-x)x(5+5 6)x=12 13km h;

The yield of rapeseed planted in a village last year reached 160 kilograms, and the oil content was 40 percent, and after planting the newly selected rapeseed this year, the yield per mu increased by 20 kilograms, and the oil content increased by 10 percentage points.

1) Compared with last year, the rapeseed planting area in this village has decreased by 44 mu, and the oil yield of rapeseed produced in the village has increased by 20% in the village oil mill.

From the meaning of the title, it can be seen that Huanhuan's family used more than 2ot water in October

Set Huanhuan's home to use t tons of water in October, then: 10*

Get t=21

Let the average speed of the train be x, (the distance from Beijing to Tianjin is equal, so).

x=240