Mathematics inequality application problems for the second grade of junior high school

Solution: (1) Yuan liter, Yuan liter.

Answer: Before the adjustment of the plan, the gasoline ** is, and the fuel tax is yuan liters;

2) It is more cost-effective to travel x kilometers per month than before the plan is adjusted, and consume 10 liters of fuel per 100 kilometers.

Fuel consumption liters per 1 km.

According to the title.

Solution x 1500;

Answer: The number of vehicles driven per month is in the range of 0 to 1500 kilometers, which is more cost-effective than before the plan adjustment

1) From the inscription, it can be seen that the fuel tax after the reform is 1 yuan, and it is more than the yuan before the reform, and the fuel tax before the reform and 93 gasoline before the reform can be obtained directly according to the title; (2) If the fuel consumption of a private car is 10 liters per 100 kilometers, the fuel consumption per kilometer is 10 100 = liters; Then let us travel x kilometers per month, according to the cost before the reform After the reform of the cost column inequality 120, the solution of the inequality can obtain the value range of x Answer: Solution:

1) Yuan liter, Yuan liter Answer: Before the adjustment of the plan, the gasoline ** is, and the fuel tax is Yuan liter; (2) Set the monthly driving x kilometers to be more cost-effective than before the scheme adjustment, fuel consumption of 10 liters per 100 kilometers fuel consumption per 1 kilometer according to the meaning of the problem 120 solution x 1500;Answer: The number of vehicles driven per month is in the range of 0 to 1500 kilometers, which is more cost-effective than before the plan adjustment

Use your own brain, do it with your hands, and learn well.

16 pcs. Let's say each worker used to make an average of x parts per day.

According to the meaning of the question, the following inequality is obtained.

x+10）*8>200

x+10+27）*4>(x+10)*8

Let's say each worker used to make an average of x parts per day.

After the first improvement of the working method, x+10 will be produced per day.

After the second improvement of the working method, x+37 units per day were produced.

1.Save on electricity bills (.)

That is, the crack guess is 80% off.

2.The drug content of the shield is x

20%< (30*15%+50x) (30+50)<35%Solution: 23%.< x "Zhenyuan 47%< p>

A kind of insecticidal powder has 30,000 grams of Zhenke, the drug content is 15%, and now it is necessary to mix 50 kg of the same insecticidal powder with a higher drug content and it, so that the mixed drug content is greater than 20% and less than 35%, then the value range of the drug content x of the medicinal powder is?

Please explain the rough answer in detail

20%<(30×15％+50x%)/80<30%23

16 designs: Each worker used to make an average of x parts per day, and according to the question, the following inequality (x+10)*8>200

x+10+27）*4>(x+10)*8

Solution 15

Let's say each worker used to make an average of x parts per day.

After the first improvement of the working method, x+10 will be produced per day.

After the second improvement of the working method, x+37 units per day were produced.

Column inequality: 4(x+37)>8(x+10)>200 solves: 15Because x is an integer, x=16

A: Each worker used to make an average of 16 parts per day.

Solution: The world set up the principal to return to attack Brother X

then 130% x 700 115% x · (1+10%) x 20000

Therefore, when the investment is greater than 20,000 yuan, you can choose to make more profits at the end of the month.

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Solution: There are a total of x people.

6x-3＜4x+37①

4x+37＜6x②

Solve the inequality yield: x 20

Solve inequality yields: x 37 2

The solution set for this group of inequalities is 37 2 x 20

x can only be taken as an integer.

x=18，,19

When there are 18 people: 4 18 + 37 = 109 (box) When there are 19 people: 4 19 + 37 = 113 (box) Answer: There are 109 or 113 boxes of water in this car.

or 0< (4x+37)-6(x-1)<3

Solution: There are x people to deliver water.

4x+37=6*(x-1)+3

Solution x=20

So 20*4+37=107

Answer:..

1. If you can also buy n pens, you can get the inequality according to the meaning of the question: (21 Solution: n

Because n must be an integer, n=5

2. It takes 0 to punch a negativeYuan??

3. There are n cars, and the inequality is obtained according to the problem: 4n+20 8(n 1) 8 solution: n 5

i.e.: n=6

1. You can also buy x pens: Solution: x 5

2. At least x people participate in the group photo: Solution: x 6

3. There are x cars: 7x 4x+20 8x solution: 5 x that is, 6 cars.

1 set to buy x arm then 3x plus.

Only by installing an X-stand can we meet the demand.

135+（10-2-3）x>=600

The solution is x>=93

i.e. at least 93 units per day.

600-135=465

A minimum of 93 units per day will be assembled within five days to meet the requirements.

5x>600-135

5x>465

x>93

Install at least 93 units per day to complete the task.

To do this kind of question, start with the question, at least how many units are installed every day, that is to say, there is a minimum value for the answer. 135 units were installed in 3 days, and there were 600-135 = 465 units left, and the remaining time was 10-3-2 = 5 days, 465 5 = 93, so the answer was to assemble at least 93 units per day.