In the first year of junior high school math problems, the solution of the application problem requi

Hello! 1.There are x number of students, x 8-x 12=2, x = 482There are a total of x rooms, 8 x+12=9 (x-2), x=30, so there are 30 dormitories and a total of 252 students.

3.Let the original time be x hours, (x-24 60) 15=(x+15 60) 12, x=3, so the original time is 3 hours.

4.Set x people in the class, x 3 + 24 = x 4-26, x = 50, so there are 50 people in the class and 174 stamps.

Finally, I wish you success in your studies!!

1.Let it be known that there is an X group so that it is known by the meaning of the question.

8x=12(x-2) gives x=6That is, there were originally 6 groups, a total of 6*8=48 people.

2.In the same way, if there are x rooms in the dormitory, then from the meaning of the question, 8x+12=9x-2 (the meaning of the equation is equal in numbers) is solved x=14There are 8 * 14 + 12 = 9 * 14 - 2 = 124 students.

3.The time is x hours, and the title is right.

15 (x-24 60) = 12 (x + 15 60) (the distance is equal, remember to convert the unit) to get x=3,4There are x people in the class, 3x+24=4x-26, x=50, and 174 stamps.

1.If there are x students, then they are originally divided into x 8 groups, and after reorganization, they are (x 8-2) groups, (x 8-2)*12=x, and x can be solved.

2.You're confusing me, how many beds are there in each room.

3.It turns out that x hours are up, 15 * x + 24 60 = 12 * x - 15 60, and x can be solved.

Zhang, x 3-24=x 4+26, solve x.

1.If there are 8 people in each group, a total of X groups, then 12 people in each group, and X-2 groups.

8×x=12×(x-2)

x=6, i.e., 8 people in each group, divided into 6 groups, a total of 48 people.

2.There are x rooms in total.

8×x+12=9×(x-2)

x = 30, i.e. 30 dormitories, 252 students in total.

The train travels at an average speed, and it takes 20s to pass through a 300m tunnel. There is a light on the top of the tunnel, which glows vertically downward, and the light shines on the train for 10 seconds. Based on the above data, can you find the train length?

If so, what is the length of the train? If not, explain why.

Use 300 20 = 15m s first

Then use 15 10 = 150m

Reason: 300 20 = 15m s is to find the speed of the train, because the light shines on the train.

It's 10s, so 10s is the time from the head of the train to the parking space, so the lead is 15 10=150 is the length of the car.

Of course, the more expensive this thing, the more cost-effective, assuming that the value of the thing to be bought is x yuan, and spending money to buy a card is the same as buying it directly, then:

200+, solution, x = 1000 yuan, that is, when the value of the thing to be bought is 1000 yuan, it is the same as buying a card directly after spending money, it is easy to know, when buying something is greater than 1000 yuan, it is more affordable to buy a card first, less than 1000 hail Hu Han, buying a card is not suitable for Hu, equal to 1000 yuan, the money spent is exactly 1000 yuan Yuan laugh.

Solution: Set the purchase price of the TV set to be X yuan.

1+20％)x=1200

x=1000

A: The purchase price of each TV is 1000 yuan.

Solve the blind trace: Set up a merchant to buy Y TV.

y=11500

y=10A: The merchant bought 10 TV socks.

Our math teacher said cover and pass:

1.Simple to concrete, concrete to abstract.

2.Break down complex problems into simple ones.

3.Multiple solutions to one question can improve the accuracy rate.

As long as you do these three points, your math score will not be low!

Solution: Set the purchase price of the TV Kai noise machine to be X yuan.

1+20％)x=1200

x=1000

Answer: The purchase price of each TV is 1,000 yuan.

Solution: The merchant who set up the world to mark the world bought Y TV.

y=11500

y=10

Solution: The price of the Chunhuai family with the TV set is X yuan and friends.

1+20％)x=1200

x=1000

A: ...Solution: The merchant bought Y TV.

y=11500

y=10A:.

Answer: Set the purchase price to x.

Because the selling price remains the same, the original selling price is the purchase price x + profit x * m%, and the later selling price is x(1-8%) (1+(m+10)%)

x(1+m%)=x(1-8%)(1+(m+10)%)The solution is: m=15

1: Set: The communicator's planned speed was x km h

5x=4(x+3) solution: x=12

2: Set: Originally sold x sets of TVs.

2500x=100000 gives x=40

Design: Sales increased Y TVs.

40 + y) multiply 2500 by the solution: y = 203: set: Xiao Ming's father deposited x yuan at that time.

x times 2 times 95% = solution x = 1920

4: Set: In October, the user used x cubic meters of gas.

Therefore, a user's gas bill in October exceeded 60 cubic meters, 60 times and 31 times

5:38-x=7 multiplied by (14-x) Solved x=6: (1+10%)x=132 Multiplied by solution x=108

1.Let v be the velocity (km h) and 4(v+3)=5v4Let the amount of coal be used x,60*, and then the amount of coal used.

1: Set the speed to x km h

5x=4(x+3) solution: x=12

2: Set: Sales of x sets of televisions.

2500x=100000 gives x=40

Design: Sales increased Y TVs.

40 + y) multiply 2500 by the solution: y = 203: set: Xiao Ming's father deposited x yuan at that time.

x times 2 times 95% = solution x = 1920

4: Set: In October, the user used x cubic meters of gas.

Therefore, a user's gas bill in October exceeded 60 cubic meters, 60 times and 31 times

5:38-x=7 multiplied by (14-x) Solved x=6: (1+10%)x=132 Multiplied by solution x=108

1.The original planned speed of the communicator was xkm h

5x=4(x+3) The solution is x=12, so the distance between A and B is 60

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.

Solution: Let the length of this train be x meters.

320+x)/18=x/10

10(320+x)=18x

3200+10x=18x

3200=8x

x=400 i.e. the train is 400 meters long.

Explanation: Because the train moves at a constant speed, the speed within 18 seconds of passing through the tunnel is equal to the speed passing through the stationary light.

Also note: the distance traveled through the tunnel is equal to the length of the tunnel plus the length of the train.

Let the train length be x, 18 seconds is the sum of the tunnel length and the train length, and 10 seconds is a train length, the speed of the train is constant, so, (320+x) 18=x 10, x=400

Let the speed of the train be V and the length of the train L.

According to the title, you can get:

320+l=18v；

l=10v；

Get: l=400

So the train length is 400 meters.

If a train moves at a constant speed, 18 seconds from the time it enters the 320-meter-long tunnel to the time it passes through the tunnel completely, and a fixed light at the top of the tunnel shines on the train for 10 seconds, then how many meters is the length of the train.

Let the length be x, then the speed is 1 10x

18 x 1／10x=320+x

Solution x=400

A: The length of this train is 400 meters.

Let the length of the train be x, we can use the speed as a unified quantity to train the equation, firstly, when the train passes through the tunnel, it takes 18 seconds, then the train travel distance is 320+x, so the speed is (320+x) 18, and the fixed light on the top of the tunnel shines on the train for 10 seconds, that is to say, the distance of the train through its own length takes 10 seconds, and the speed is x 10.

320+x）/18=x/10

The solution is x=400, which means that the length of the train is 400 meters.

Set the commander to x...

The speed is (320+x) 18...

The velocity is x 10 again, and (320+x) 18=x 10 gives x = 400 meters.

The solution process is as follows:

There are x classes in the primary school:

Because "if each shift is divided into 10 sets, then there are 5 sets left", so the number of Fuwa = 10x+5

And because "if the previous class is divided into 13 sets per class, then the last class is divided into Fuwa, but only 3 sets", so the number of Fuwa = 13 (x-1) + 3

The number of Fuwa is certain, so the above two formulas are equal:

10x+5=13(x-1)+3

The solution is x=5, that is, there are 5 classes in the primary school, and the total number of Fuwa is 55.

Suppose a win of 6 matches 18 points does not match.

Suppose a win of 5 games with at least 15 points does not match.

Assuming a win of 4 games and a draw of 2 games and 14 points meet.

Suppose 3 wins, 3 draws, 12 points do not match.

Team A has won 4 games.

Let's say A wins x games.

3x+（6-x)>13

3x<15

Get x>3 and x<5x=4