A math problem won t be rushed!!

The answer I calculated was that A and B were 150km apart

Let the speed of the truck be x; The speed of the motorcycle is y; The distance between the two places is 60 --- B --- LA.

A---30--B.

60/x)*y=l-60; .You can push out y=(l-60)*(x 60) = lx 60 - x .

l+30)/x)*y = 2l-30 ..

Substituting can be deduced (lx+30x)*(lx 60-x)=2l-30, in which case x=1, then (l+30)*(l 60-1)=2l-30l 60-l+l 2 = 2l (l here represents the square of l), l -60l+30l = 120l

l -150l=0 Finally, l=150(km) is solved

Maybe 80 km. The problem may be a problem in itself!!

Solve the system of equations, it's easy!

60 km away from A, and then 30 km away from B, if the speed of the two vehicles is the same, it is 30 60 90

The study should be based on the special circumstances method. Like this one. It will be more useful in the future.

Suppose the truck departs from place B, the motorcycle departs from place A, the truck travels 60 kilometers, the motorcycle travels x kilometers, then the motorcycle travels 90 kilometers, and the truck travels 2x+30 kilometers.

The trucks went 60 kilometers and the motorcycles went x kilometers.

Trucks went 2x+30 km, motorcycles went 90 km, 60 vs. 2x+30 x vs. 90

x 30 root number 3

x 45 total distance 45+60 105

Suppose the truck departs from place A, the motorcycle departs from place B, the truck travels 60 kilometers, the motorcycle travels x kilometers, then the motorcycle travels 120 + 30 kilometers, and the truck travels x+30 kilometers.

60 to 30+ x x to 150

x is approximately equal to 15

Total distance 75

That's how it should be.

Let the distance be s, and the speed of the two cars is V1 and V2 respectively

60/v1=（s-60）/v2 ..

s-30)/v1=(s+30)/v2 ..

v1 (v1+v2)=60 s .

v2 (v1+v2)=90 s .

1=150 s

So s=150km

What is the distance of the first one 60 km? You can set ab to the speed of 2 cars. Soon c is set to the distance.

The ratio of return speed is 1500:1200 5:4

The time ratio is 4:5

Go to time 6x4 (4+5)=8 3

Fly 1500x8 3=4000km.

A: The plane can fly up to 4,000 kilometers before it needs to fly back.

Set up to fly x km.

x/1500+x/1200=6

9x/6000=6

x=4000

Fly up to 4000 km.

Set the total purchase price to be $x.

500+（x-500)*(1-20%)=2500x-500=2500

x=3000

Its total shopping price is 3,000 yuan.

2500-200 = 2000 yuan, 2000-2000 * 20% = 1600 yuan.

1600 + 500 = 2100 yuan.

I guess so.

Set the total shopping price to be x yuan, (x-500)*(1-20%)+500=2500, solution, x=3000 yuan.

2500 + (2500-500) * 20% = 2900 (yuan).

A: Its total shopping price is 2900 yuan.

Solve with a quadratic equation.

The actual wall is only 3+6=9 meters; 9+27=36m, 36 2-18m. That's easy to calculate.

Set: x m long and (18-x) m wide. Solution: x(18-x)=8018x-xsquare=80 xsquared-18x+80=0 Quadratic equation solution cross multiplication:

x-10) (x-8) = 0 x1 = 10 x2 = 8 (discarded if not in place) 10 (18 -10) = 10 8 = 80 square meters. A: The length of the rectangle is 10 meters and the width is 8 meters.

1 (10+2) 2=6m 10 2=5m 6*6*square meters.

A: The area of this ring is square meters.

2 7/10 divided by 4 gives 7/40m 7/40 multiplied by 7/40 equals 49/1600

A: Its side length is 7/40 of a meter, and its area is 49/1600 of a square meter.

3 [3/4-0 divided (1/7 + 2/13)] x1 and 1/4 = 3/4 x 1/4 = 15/16

There is nothing left to do.

I didn't understand questions 1 and 3, and I answered 2 questions: 7/40 of the side length, 49/49/1600 of the area

The original plan took x hours to complete.

28*（x-10）=20*(x-6)

28x-280=20x-120

28x-20x=-120+280

8x=160

x=20 so the original plan would take 20 hours.

So there are 28*(20-10)=280 parts.

Solution: Use a proportional approach.

Assuming that the original plan is completed in x hours, the time taken is inversely proportional to the number of processing, so there is.

28/20=(x-6)/(x-10)

Get x=20, so this batch of parts 20 (x-6)=280.

1) How many people were employed in 2004

200 (person).

The total annual income of the people who have been lifted out of poverty and become rich has reached 15% of the total investment at the beginning of the year, and the per capita annual output value of the total output value of the employed persons is 50,000 yuan).

2) The annual comprehensive benefits of the whole project after completion

Annual comprehensive benefit = annual gross output value of employed persons + total income of persons who have been driven out of poverty and become rich) The number of employed persons after the completion of the project.

392 (person).

The total annual output value of employed persons is ——

10,000 yuan) after 2006, the average annual growth percentage of employed persons is twice the average annual growth percentage of investment in the first two years of 2006, the per capita annual output value is 50,000 yuan, and the per capita annual output value will increase by 2,000 yuan per year).

The total income of people who have been driven out of poverty and become rich——

294 (10,000 yuan).

The per capita annual income of those who were lifted out of poverty in 2008 was twice that of those who were lifted out of poverty and become rich in 2004

Annual comprehensive benefit - 10,000 yuan).