About a few middle school math problems which require a process and are solved with equations .

If you remove Ax, you will go to B20-x

27+x=2*(19+20-x) x=17, so 17 people at A and 3 people at B.

The teacher bought 25 pens for himself and 35 pens for his colleagues, spending a total of 240 yuan.

A and B cooperate at a speed of 1 4 + 1 6 = 5 12

B does 1 6, A and B cooperate to complete the remaining 5 6 need (5 6) (5 12) = 2

Then A did (1 4) * 2 = 1 2, so B also made 1 2 and got 300 yuan per person.

1. If you go to A x, then go to B 20-x

27+x=2*(19+20-x) x=17, so 17 people at A and 3 people at B.

2. The husband and wife work on the construction site, the woman is 25 yuan a day, the man is 35 yuan a day, and after the work, he gets 240 yuan. Q: How many days did the couple do it?

3. If this batch of parts has a total of A pieces, A can make 1 4 A per day, and B can make 1 6 A per day. Set A and B to do it together for x days.

From the meaning of the question: 1 6 a+(1 4 a+1 6 a)x=a, x=a, x=2

Therefore, the parts made by A are: 1 4 A * 2 = 1 2 A and B is made of: 1 6 A + 1 6 A * 2 = 1 2 A so A and B both get 300 yuan.

1.If X people should be transferred to A, then B (20-x) so (27+x) 19+(20-x)=2 gets x=17, so 17 people should be transferred to A, and 3 people in B.

2.There are 25 female students in Xiao Ming's class, and 35 male students fold a total of 240 origami airplanes. Only.

1. Solution: Let the number B be x, then the number A is 5x, according to the title, the number A is 48 more than the number B, that is, the number of masking 5x-x=48, that is, 4x=48, the solution is x=12, that is, the number B is 12, and the number A is 48

2. If the flour is x kg, then the rice is 5x kg, according to the title, the rice is 720 kg heavier than the flour, that is, 5x-x = 720, that is, 4x = 720, the solution is x = 180, Xiaohezhou is 180 kg of flour, and the rice is 180x5 = 900 kg.

Over, I hope that the landlord will ponder the similarities between the two questions and draw inferences.

Set the barrel to weigh a kilogram, millet to weigh (30-a) kilograms.

It should be exchanged for rice (30-a) 2 = (15-a 2) kg, and rice should be exchanged for rice = (15-a) kg.

Should be exchanged for rice - actual rice = (15-a 2) - (15-a) = a 2 kg Therefore, the amount of rice that Uncle Zhang loses is equal to half of the weight of the barrel = a 2 kg.

Suffer a loss of barrel weight x (kg).

Xiaomi weighs 30-x

You can get (30-x) 2, ie.

In fact, Uncle Li weighed 15 kilograms of rice for Uncle Zhang with a bucket of rice, that is, he gave 15-x (kg) of rice

Uncle Zhang suffered.

The weight of the bucket is x kilograms Then the weight of the millet that Uncle Zhang gave to Uncle Li is: 30-x, and the weight of the rice that should be exchanged is: [30x] 2=15-x 2 And in fact, the rice that Uncle Li gave Uncle Zhang weighed:

15-x It is obvious that Uncle Li gave less, that is, Uncle Zhang suffered a loss, and he lost: [15-x 2]-[15-x]=x 2 That is, he lost half a bucket of rice. References

Set the barrel weighs x kilograms, and millet weighs (30-x) kilograms.

Rice (30-x) should be exchanged for 2 = (15-x 2) kg, and rice should be exchanged for = (15-x) kg.

Should be exchanged for rice - actual rice = (15-x 2) - (15-a) = x 2 kg Therefore, the amount of rice lost by Uncle Zhang is equal to half of the weight of the barrel = x 2 kg.

Uncle Zhang lost.

Set the bucket to weigh x kg, Uncle Zhang's millet can be exchanged for (30-x) 2 kg of rice, that is, 15-x 2 kg.

And in reality only (15-x) kilograms, so it was lost.

If the bucket weighs x kg, the weight of millet is 30-x kg, the weight of rice that can be exchanged is (30-x) 2 kg, and the actual weight of rice is (15-x) kg (30-x) 2 - 15-x) = x 2 kg What can be exchanged is more than what is actually exchanged, so it is a loss Half of the weight of the barrel.

Lost. Let the barrel be x kilograms. In this way, millet is 30-x kilogram Because every 2 kilograms of millet can be exchanged for 1 kilogram of rice, so, it can be exchanged for one-half of (30-x), and Uncle Li weighed 15 kilograms of rice for Uncle Zhang with a bucket of rice, that is, Uncle Li gave Uncle Zhang 15-x kilograms of rice, because x is greater than 0, so Uncle Zhang loses, and loses 1/2 of x.

Set up a 5-ton truck full load x times.

Total weight = 5x+3

It is also equal to =3(x+7)+2=3x+23

The columnable equation is 3x+23=5x+3

Solution: x=10

So the total weight is 5*10+3=53 tons.

5 tons of trucks need to be transported 10 + 1 = 11 times.

3 tons of vehicles need to be used 10 + 7 + 1 = 18 times.

Suppose this batch of goods totals x tons, and the truck is transported Y times.

y+7）*3+2=x

5y+3=x

Calculate that y is 10 and x is 53

So the cargo has a total of 53 tons, and the truck can be transported in 10 times.

1.Let this number be xyz, then there is x+y+z=24,x-y=2,(100x+10y+z)-(10x+x)=(100z+10y+x); The solution is x=9, y=7, z=8, so the answer is 978.

2.Let the number in the single digit be x and the number in the ten digit be (10-x), 10x+(10-x)=10(10-x)+x+36; Solve the equation: x=7, (10-x)=3, so the original number is 37!

Type X stage, B type Y stage.

x+y=36

6000x+4000y=100500

The solution is x=, impossible.

Type A X stage, C type Y stage.

x+y=36

6000x+2500y=100500

The solution is x=3, y=33

Type B X stage, C type Y stage.

x+y=36

4000x+2500y=100500

The solution is x=7 and y=29

Two schemes: 3 units of type A and 33 units of type C; 7 units of type B, 29 units of type C 4Set up the production of a product x (t) and b product y (t), according to the theme, get.

900x+1000y=530000

Solution x=200

y=3505.The speed of the train is x s 15x+15m=17x-15m x=15m s, and the train is 15x+15=230m

You are from Hangzhou, no.

1. Let the original three digits of hundreds of digits be a, ten digits of b, and single digits of c, then a+b+c=24

a-2=b100a+10b+c-(10a+a)=100c+10b+aSolve the above equations, you can know the values of a, b, and c, then the original three-digit number can be known.

2. Let the original two-digit ten-digit number be x and the single-digit number be y, then x+y=10

10y+x-36=10x+y

If you solve the above equations, you can know the values of x and y, and the original two digits can be known.

3. Three combinations: (1) buy A and B, (2) buy A and C, (3) buy B and C, and (1) buy A and B. If you purchase an AX unit and a BY unit, it will be 6000x+4000y=100500

x+y=36

Solve the system of equations to know the values of x and y.

2）、（3）……Same as above).

Note: x and y are the number of computers, and the school wants to buy two kinds of computers, so the value of x and y can only be positive integers, if not positive integers, then this kind of scheme is discarded).

4. Set up the production of a xt, the production of b yt, then.

2x+1000x+900y=530000

Solve the above equations, and the values of x and y can be known. When producing the tons of A and B, the raw materials and funds are just used up.

5. Let the train speed be xm s.

1+x）×15=（x-1）×17

Solve x=16

The train speed is 16m s

Vehicle length = 16 15 + 1 15 = 255m

One. x+y+z=24

x-y=2100x+10y+z-(10x+x)=100z+10y+x; The three-digit number of meta is 978

Two. x+y=10

10x+y-x-10y=36

jie: The original two-digit number 37

Three; There is a 500 yuan in the total amount of the number first, so it will not be selected at the same time, then it can only be and a+c=36 6000a+2500c=100500 and b+c=36 4000b+2500c=100500 Buy so much must be discounted.

Four. 2a+1000a+900b=530000 a=350 b=200

w five. The speed of the train is x s 15x+15m=17x-15m x=15m s, and the train is 15x+15=230m

Definitely not in junior high school, in the fifth grade of elementary school.

1.(1) Solution: Let x seconds later.

then 4x+6x=400

10x=400

x=40A: Meet after 40 seconds.

2) Solution: Set Y seconds to meet later.

Then 6y-4y=400

2y=400

y=200A: Meet after 200 seconds.

2.Solution: The speed of sailing when set in still water is x

then (x+2)*4=(x-2)*5

x=18A: The speed of the ship in still water is 18 kilometers per hour.

1, solution (1) set x seconds after they meet.

then there is 4x+6x=400

Solution x=40

2) Set x seconds after they meet for the first time.

then there is 6x-4x=400

Solution x=200

2. The speed of the ship in still water is x

Then 4(x+2)=5(x-2).

The solution is x=18

1.Let x seconds meet, 1)x*(4+6)=400 to get x=40(2)x*(6-4)=400 to get x=2002Let the speed be x and the distance be s (not used).

Downstream s=(x+2)*4

Countercurrent s=(x-2)*5

x=18

1. Analysis: According to the idea of engineering problems, the burning efficiency of the first candle is 1 60, and the burning efficiency of the second candle is 1 80

Because the first one burns quickly, if one of them is half of the other, it can only be that the first is half of the second.

After x minutes, we can give the equation: 1-x 60=(1-x 80) 2 gives x=48

The answer is 48 60=hours.

2. 1) If this team wins x games, it will draw (7-x) games.

3*x+1*（7-x）=17

x=52) has the highest score in the next 6 games, with a score of 17+3*6=35

The maximum score is 35 points.

3) Of all the situations where the goal is reached, the least number of games will be won except in the case of a tie. Set x number of wins.

then 3*x+1*(6-x)=29-17x=3

1.Let the length of one of them be half the length of the other after t minutes, 1-1 60t = solution to t = 48

2.Suppose this team wins x games, then it draws (7-x) games.

3x+7-x=17

With 18 points in all six games after x=5, this team can score a maximum of 35 points in 14 games.

Set for the next 6 games, this team will have to win at least x games to reach the desired goal.

Rule. 3x+6-x=12x=3

Solution: You may wish to set the candle that can burn for 60min as A, and the other candle that can burn for 80min as B, and their length is A. Then A burns a 60 per minute, B burns a minute and A is half of B after a minute.

The columnable equation is: 2*(a-ax 60)=a-ax 80 solution: x=48 minutes.

3 hours set the length of the candle to l, the time required is x: 2*(l-l 4*x)=l-l 6*x solution: x=3 hehe 2 hours 2shi (6-x) (4-x)=2 x=2 1-x

1.This team has won 5 of the first 8 games.

2.This team played 14 games and scored a maximum of 35 points.

3.Solution: This team still has to win x games.

3x+17=29

3x+17-17=29-17

3x=12x=4

4.(x-9)/x=1/10 x=10

7.The height of each floor is 42 (15-1) = 3 meters, and 3 (6-1) = 15 on the sixth floor

8.(8 3) *1 3 = 8 9 1 9 left