There are 100 simple problems to solve column equations

Let us transport x tons from the first pile to the second pile, 145-x+2=97+x, 2x=50, x=25

After transporting 25 tons from the first pile to the second pile, the second pile is 2 tons more than the first.

Set up two cars to meet in x hours.

50x-40x=20×2,10x=40,x=4,40+50)×4

360, A and B are 360 kilometers apart.

(1) The store sells a point reading machine, if the price of each unit is 600 yuan, then 70% of the selling price is the cost, and 30% of the selling price is the profit. Now to carry out ** activities, in order to ensure that the profit of a point reader is not less than 90 yuan, how should the discount be determined?

The discount cannot be less than 85% off.

2) Wang Yu's house is 800m due south of the library, and Li Gang's house is 750m due north of the library. On Saturday, the two made an appointment to go to the library to read books. The two set off from home at the same time at 8:30 a.m., Wang Yu walked 75m per minute, and Li Gang walked 80m per minute.

Li Gang walked to the library and didn't see Wang Yu, so he continued to walk south. How far were the two from the library when they met?

Solution: If the two people meet x meters away from the library, then.

750+x) 80=(800-x) 75 (based on the equation that two people walk for equal time).

75*750+75x=64000-80x

solution, x=50

So the two were 50 meters away from the library when they met.

3) 2 teachers and 40 students went to the park to row boats, each big boat can seat 6 people, each small boat can seat 4 people, a total of 10 boats were rented, and there were no vacancies on the boat. How many large boats and small boats are there?

Solution: If there are x large boats, then there are 10-x small boats.

6x+4(10-x)=40+2

6x+40-4x=42

2x=2x=110-x=9

A: If there is 1 large boat, there are 9 small boats.

Solution: Set up workshop A and B to produce instruments every day are x, Y sets, workshop A produced instruments Z before the high speed, then, 1) by "when workshop A produced 20 instruments, the number of instruments produced by the two workshops since the start of construction is exactly equal".

20/x)*y=z+20;

2) It is known from "at this time, workshop A shared 8 days".

z+20=8x；

3) From "the number of instruments produced by workshop A before adjustment, workshop B can complete it in only two days" to know z=2y

Simultaneous (1), (2), (3) get a system of equations, substitute the equation of (3) into the equation of (2), and obtain, 2y+20=8x, that is, x=(y+10) 4, and then substitut (1) to obtain.

y^2-20y+100=0，（y-10)^2=0，y=10.

Further, x=5, z=20

A: Workshop A produced 20 instruments before the adjustment.

1.A flock of swallows was flying, and a lone swallow flew towards them, and it said to them: Hello, 100 swallows!

One of the swallows who took the lead said, "No, we are not 100 swallows, but listen, add to our group of swallows a flock of swallows of the same number as us, add half a flock of swallows, add a quarter of the flock of swallows, and add you to make a total of 100 swallows." How many swallows are there in this flock?

Solution: Let's say there are x swallows in this flock.

x+x+1/2x+1/4x+1=100

11/4x=99

x=362.A rides a bicycle from A to B, and B rides a bicycle from B to A, and A rides 2 kilometers and hours faster than B. The two set off at the same time at 8 a.m., and by 10 a.m. they were 36 kilometers apart, and by 12 noon they were 36 kilometers apart.

Find the distance between A and B.

Speed sum: (36+36) 2=36 (kmh) distance between a and b: 36x2+36=108 (km).

1.Let this group of swallows be x

x+x+1/2x+1/4x-1=100

11/4x=100-1

11/4x=99

x=36A: There are 36 swallows in this flock.

km (8-10 o'clock 36 apart.)

Solution: Let the speed of the ship in still water be xkm and the speed of the current be ykm

then 7(x+y)=224

8(x-y)=224

Lianli solution. x=30，y=2

Answer: The speed of the ship in still water is 30km, and the speed of the current is 2km

Suppose the velocity of the ship in still water is xkm h and the velocity of the current is ykm h, then {7(x+y)=224

8（x-y）=224

Solve the system of equations to obtain:

x=30y=2So, the speed of the ship in still water is 30 km h, and the current speed is 2 km h

Solution: If the speed of the ship in still water is v km, the current velocity is v km according to the title: 224 (v+v water)=7

224 (v-v water) = 8

Solution: v = 30 kmh.

v water = 2 km h.

You can set two unknowns, the speed of the boat in still water is the speed of the ship x, the speed of the current is y and the speed of the water is x+y, and the speed of the reverse water is y-x

7（x+y）=224

8（y-x）224

x=2, y=30

Let the speed of the ship in still water be a and the speed of the current be b

a+b)*7=224, (a-b)*8=224 gives a=30, b=2

Answer: The speed of the ship in still water is 30km h, and the current speed is 2km h

Let the water speed be x and the ship speed be y

224/（x+y)=7

224/(y-x)=8

y=30 so the speed of the boat in still water is 30km h

Let v be the speed of the ship and u be the speed of the water, then there is:

224=(v+u)*7

224=(v-u)*8

Therefore, the solution is v=30km h, u=2km h

1.Solution: Set the number of deposits of A to be X million yuan.

Answer: A and B have deposits of 50,000 yuan and 150,000 yuan respectively.

2.Set: The shareholder originally **X shares**. 1x=

Answer: The shareholder originally bought 1391 shares.

It can only be said that it is very simple - -

Solution: Set up to complete the project A and B cooperation x days.

3/12+(1/12+1/8)x=1

5/24x=3/4

x=24/5

Answer: To complete this project, A and B cooperate for 24 and 5 days.

Completion of this project A and B cooperation x

1/12 *3+ （1/12+1/8）x=15/24x=1-1/4

5/24x=3/4

x=18/5

Set this batch of English words to learn in x days.

15+5）x=15×20

The solution is x=15

Set x days to finish.

20*15=（15+5）*x

x=15 This batch of English words Chubby is used to learn in 15 days.

Solution: Set x days.

20*15=（15+5）x

350=20x

x = A: It can be completed in 15 days.