A mobile communication company in a certain place has set up two kinds of services: the monthly rent of "Globallink" is 30 yuan, and the call fee per minute is 0.2 yuan; Shenzhouxing has no monthly rent, and the call fee per minute is 0.4 yuan (both of the two kinds of calls refer to urban calls). If the call is x (min) within a month, which communication service is more cost-effective?

According to the meaning of the title, the monthly call cost of "GLOBCOM" is (30 + 0.2x) yuan, and that of "Shenzhouxing" is 0.4x yuan. Then, the solution of (30 + 0.2x ＞ 0.4x, - 0.2x ＞ - 30) is x ＜ 150, that is, when the call time is less than 150 min, "Shenzhouxing" is cost-effective. ② the solution of (30 + 0.2x = 0.4x, - 0.2x = - 30) is x = 150, that is, when the call time is 150 min, the two services charge the same. ③ 30 + 0.2x ＜ 0.4x The solution of - 0.2x ＜ - 30 is x ＞ 150

Square ABCD, DP intersect AC at m, intersect AB at n, the extension of intersecting CB at P, PN = 3, Mn = 1, find the length of DM

Drawing can be more intuitive
Triangle anm and triangle CDM are similar triangles
because
NM:DM=1:DM=AN:CD
AN=AB-BN=CD-BN
therefore
1:DM=(CD-BN):CD=1-BN:CD
because
BN:CD=PN:PD
PD=PN+MN+DM=4+DM
BN:CD=3:(4+DM)
So 1: DM = 1-3: (4 + DM)
DM=2

What is the 1000 power of 2

10715086071862673209484250490600018105614048117055336074437503883703510511249361
22493198378815695858127594672917553146825187145285692314043598457757469857480393
45677748242309854210746050623711418779541821530464749835819412673987675591655439
46077062914571196477686542167660429831652624386837205668069376

1. The starting price of a taxi is 5 yuan. After 2 kilometers, it will be charged at 1.2 yuan per kilometer. Xiaoming's place is 20 kilometers away from here. How much does it cost at least?
Uncle Wang, the driver, refilled 30 liters of gasoline at the gas station and went to work in a company 180 kilometers away from the gas station. How many liters of gasoline would he need when he came back according to 8 kilometers per liter of gasoline

1. At least
=5+1.2×（20-2）
=5+1.2×18
=26.6 yuan
2. We need gas
=180×2÷8-30
=45-30
=15 liters

If the length of a rectangle is extended by 5 cm, its area will be increased by 60 square cm. If the width is shortened by 5 cm, its area will be reduced by 100 square cm

What are you asking?
It's 20 long and 12 wide. Is this it?

In △ ABC, a is the minimum angle, B is the maximum angle, and 2 b = 5 A. if the maximum value of B is m ° and the minimum value is n °, then M + n=______ ．

∵ 2 ∠ B = 5 ∠ a, i.e. ∵ B = 52 ∠ a, ∵ C = 180 ° - A - ∠ B = 180 ° - 72 ∠ a, and ∵ a ≤ ∠ C ≤ ∠ B, ∵ a ≤ 180 ° - 72 ∠ a, i.e. ∵ a ≤ 40 °; and ∵ 180 ° - 72 ∠ a ≤ 52 ∠ a, i.e. ∵ a ≥ 30 °, and ∵ 30 °≤ ∠ a ≤ 40 °, i.e. ∵ 30 °≤ 25 ∠ B ≤ 40 °, and ∵ 75 °≤

1. The mass of an empty bottle is 400g, and the total mass of the two is 800g when it is filled with water; when it is filled with another liquid, the total mass is 720g, Q: what kind of liquid may be filled?
2. Put the 54G aluminum block into the cup filled with water gently, the quality of spilled water is 20g, if put into the cup filled with alcohol, calculate the quality of spilled alcohol
3. The mass of a hollow aluminum ball is 27g. After the hollow part is filled with alcohol, its total mass is 59G (ρ alcohol = 0.8 × 103kg / m3, ρ aluminum = 2.7 × 103kg / m3)

The second question is that 54 grams of aluminum block is redundant, and 20 grams of water is 20 ml
The volume of aluminum block remains unchanged, and the spilled alcohol is 20ml. Directly multiply 20ml by alcohol density of 0.8
The first question contains water 800g-400g = 400g, that is 400ml
Unknown liquid weight 720g-400g = 320G, density 320G / 400ml = 0.8g/ml, may be wine
The volume of aluminum sphere is hollow, that is, the volume of alcohol plus aluminum
Alcohol weight 59g-27g = 32g volume 32g / 0.8g/ml = 40ml = 40cm3
Aluminum volume 27g / 2.7g/cm3 = 10cm3
The volume of the ball is 40 + 10 = 50 cm3

A piece of iron wire can just form a square with a circumference of 4.71 meters. If the iron wire is used to form a circle, how many square meters is the area of the circle?

Circle radius = 4.71 / (2 * 3.14) = 0.75m
Area = 3.14 * 0.75 * 0.75 = 1.76625m2

2n + 1 power of 2 + n power of 4 = 48 n =?

2^（2n+1）+4^n=48
2^（2n+1）+2^2n=48
（2^2n）×（2+1）=48
2^2n=16
2n=2
n=2

Who has the problem of rational number calculation

1. A cylindrical timber is 2 meters long, cut into three equal sections, and the surface area increases by 24 square centimeters. How many cubic centimeters is the volume of the original timber?
2. The circumference of the bottom surface of a cone-shaped wheat pile is 12.56 meters and the height is 1.2 meters. If the wheat weight per cubic meter is 500 kg, how many tons does the pile weigh?
3. A rectangle is 8 cm long and 4.56 cm wide. What is the area of a circle equal to the circumference of the rectangle?
4. The area of a triangle land is 0.8 hectare. Its bottom is 400 meters. How high is it?
5. A piece of white cloth is a square with a side length of 2 meters, cut into a right angle, and the side is a small triangle towel with an isosceles right angle of 2 decimeters. How many pieces can be cut at most?
6. Use 12.56 decimeter long lead wire to form a square and a circle respectively. How much more is the area of the circle than that of the square?
7. Xiao Hong read 54 pages of a story book in three days. According to this calculation, how many days will it take to finish reading 162 pages of the book
8. There is an isosceles triangle. The degree ratio of its two angles is 1:2. What kind of triangle can this triangle be classified by angle?
9. A batch of cloth is processed by the weaving factory, which is completed by Party A and Party B in 16 days, Party A alone in 20 days, and Party B weaves 600 meters per day. How many kilometers of this batch of cloth are there in total
10. Party A and Party B drive in opposite directions from the same place. Party A starts at 6 pm and travels 40000 meters per hour. Party B starts at 4 am the next day. After 10 hours, the distance between the two cars is 1080 km. What's the speed of Party B?
11. When a machine tool factory manufactures a certain kind of machine tool, it uses 1.5 tons of steel for each machine tool. In fact, it saves 0.25 tons for each machine tool. As a result, it manufactures 10 more than the original plan. How many machine tools did it originally plan to build?
12. Xiao Wang bought a batch of toothbrushes at the wholesale price of 0.35 yuan per toothbrush and the retail price of 0.40 yuan per toothbrush. When there are 200 toothbrushes left unsold, Xiao Wang calculated that he has made a profit of 200 yuan after deducting all the costs. How many toothbrushes did the shop buy?
13. Salt is completely dissolved in water and turns into salt water. It is known that the weight ratio of salt to water in a certain salt water is 1:10.500 g. how many kilograms of water should be added to salt?
14. To build a road, 20% of it was built in the first five days. According to this calculation, how many days will it take to complete the road?
15. The original price of a washing machine is 1450 yuan. Now it is sold at a 20% discount, but the price is still 1 / 9 higher than the cost?
16. To build a new road, the actual investment was 1.588 million yuan, which saved 212 thousand yuan compared with the original plan. What percentage of the saving?
17. It takes 10 hours for team a and 15 hours for team B to complete a project alone. Now team a works alone for 2 hours, and the rest of team B is working. How many more hours will it take to complete the task?
18. Xiao Lin went to school from home at 7:30 in the morning. He walked 50 meters per minute. When he arrived at the school gate, he found that he didn't have his math book with him. He immediately went back along the original road and walked 70 meters per minute. It was just 7:54 when he got home. How many meters is Xiao Lin's home from school?
19. A cuboid warehouse is about 9 meters long, 6 meters wide and 5 meters high. If you put it into a square wooden box with an edge length of 2 meters, how many can you put in at most?
20. The accountant of a factory found that there was an extra 273.6 yuan in cash. After checking the accounts, he found that there was a mistake in the decimal point of an expenditure. How much is the sum?
21. A paper mill has carried out the household saving campaign, saving 1.44 tons of coal every day. If 3 kg of coal can be used for 7.5 degrees of power generation, how many degrees of power generation can be saved every day?
22. The decimal point of a certain number is moved one place to the left, which is 41.4 less than the original number. What is the original number?
23. The area of a triangle is 18 square centimeters, and its bottom is 12 centimeters. How high is it?
24. When a box of soap is distributed to workers in a workshop, the average person can be divided into 12 pieces. If it is only distributed to female workers, the average person can be divided into 20 pieces; if it is only distributed to male workers, the average person can be divided into how many pieces?
25. The profit of a commodity is 20% of the cost. If the profit is increased to 30%, how much should the selling price be increased?
26. There is an oil mill that can extract 38 kg of oil from 100 kg of rapeseed. How many kg of rapeseed is needed to extract 1 kg of oil? How many kg of oil can be extracted from 1 kg of rapeseed?
27. Fold the 48 cm long wire into a right triangle with the ratio of three sides of 3 ∶ 4 ∶ 5, and calculate the area of the right triangle
28. Xiaohong's family has a barrel of oil that weighs 8 kg. After half use, the barrel still weighs 4.5 kg. How many kg is the original oil?
29. It takes 8 days for team a to build a 10 km road, and 12 days for team B. how many days does it take for the two teams to complete the joint construction?
30. The area of a rectangular flower bed is 6 square meters. If the length is increased by 1 / 3 and the width is increased by 1 / 4, how many square meters will the area increase now?