To decorate a new house, if a and B cooperate, it will take 6 weeks, and the cost will be 52000 yuan; if a company does it alone for 4 weeks, the rest will be done by B company, and it will take 9 weeks, and the cost will be 48000 yuan. If only one company is selected to finish it alone, from the perspective of saving expenditure, which company should be chosen? Please explain the reason Company B

To decorate a new house, if a and B cooperate, it will take 6 weeks, and the cost will be 52000 yuan; if a company does it alone for 4 weeks, the rest will be done by B company, and it will take 9 weeks, and the cost will be 48000 yuan. If only one company is selected to finish it alone, from the perspective of saving expenditure, which company should be chosen? Please explain the reason Company B

A 6 weeks + B 6 weeks = 52000 (1)
Week a 4 + week B 9 = 48000 (2)
(1) The results showed that the ratio of × 3 - (2) × 2 was 60 000 in 10 weeks for a, 60 000 in 1 week for a, and 4 / 150 000 in 1 week for B
The price of a week is less than that of B, so we choose B company

Such as the question! What is the basis of junior high school must learn?

1. What is rational number, real number, will distinguish between rational number and natural number and real number; 2, equation and function: unary linear equation, unary quadratic equation, unary quadratic equation, unary linear function, quadratic function and inverse proportion function

If you can,

Mathematics
I want to connect the formulas of grade one and grade two with some things that must be written down, so that there will be no big problem. In my experience, in the 2009 high school entrance examination, half of the subjects with medium difficulty and 10% of the subjects with South difficulty are in the middle, and the rest are very simple. As long as you are careful and calculate correctly, there should be no problem. By the way, there are a lot of math questions in the high school entrance examination, From now on, you have to do the questions regularly (you are not allowed to use the calculator in the senior high school entrance examination), so you have to exercise the speed of doing the questions from now on
Physics
This follows the teacher's progress. In the third year of junior high school, the teacher will rearrange the focus of the past two years. You can listen carefully. The teacher's test paper and some homework must be done carefully. In fact, physics in the senior high school entrance examination is not difficult. As long as the homework assigned by the teacher is done well, there is no big problem
history
This is more simple, that is, reciting. I am familiar with all the six books. I recited the five books in the second semester of junior one, the second and the third year of junior high school. I memorized them at that time. I took the time to finish my homework every day, and then endorsed them. Arts is reciting! ~ ~ the teacher should also send handouts, that is to say, you recite what the teacher asked you to recite. I remember my time, In fact, it's of little significance to recite history. As long as you are familiar with history and look at the problems, you will know it immediately. In addition, you should learn to sort out knowledge, connect these characters and events together, and remember what major events happened in that year. Recite the key points, and the rest should be no problem. Recite them according to the current political hot spots, It's very possible to test some hot issues in current politics, as if that's all
In addition, I wish you all the best in the exam

The equation 2y-6 = y + 7 is transformed into 2y-y = 7 + 6, which is called______ According to______ ．

2y-6 = y + 7, transfer term: 2x-y = 7 + 6, according to the nature of the equation 1. So the answer is: transfer term, the basic nature of the equation 1

In the equal ratio sequence {an} (n ∈ n *), if A1 = 1, A4 = 18, then the sum of the first 10 terms of the sequence is ()
A. 2−128B. 2−129C. 2−1210D. 2−1211

From A4 = a1q3 = Q3 = 18 {q = 12, so S10 = 1 − (12) 101 − 12 = 2 − 129

"Success" and "merit"
1. What are the examples of the characters in the passage to illustrate "success comes naturally"
2. What's the inspiration of "dripping wears away stone"
3. Use the word "success" and write your harvest after reading this article in one sentence
4. It's better to stand up and accumulate your own merits than to sit and admire others' achievements
How do you understand "sit" and "stand" in the sentence "stand"?

1、 What are the examples of the characters in the passage to illustrate "success comes naturally"
1. Wang Xizhi, a great calligrapher of Jin Dynasty, made great achievements in calligraphy after 20 years of hard training
2. Li Shizhen worked hard for decades to write the great work compendium of Materia Medica
3. Only when Sima Qian was tortured by the palace and didn't give up, could historical records be born
2、 What's the inspiration of "dripping wears away stone"
Since the weak water drops can drop through the hard stone, no matter how weak the previous study foundation is, as long as we are willing to accumulate energy, we can break through many obstacles and achieve excellent results
3、 If you want to succeed, you must be good at accumulation
4、 Looking at the success of others, it's better to let yourself work hard and strive for achievements. Don't envy others + you have a hard heart = success

After reducing the height of a cylinder by 4cm, the surface area will be reduced by 50.24cm2, and the volume of the reduced part will be calculated

50.24/4 = 12.56 cm
12.56/3.14/2 = 2 cm
3.14 * 2 * 2 * 4 = 50.24 cm3

How many years will the earth live?

The earth's current life span is 4.6 billion years. As for how long the earth will exist in the future, it is still unknown. Here are the reference materials. How long is the life span of the earth? It is speculated that the earth has survived for 4.6 billion years. But how long can it live? Scientists believe that if the earth is allowed to run freely, it may exist forever, but if there are other external factors interfering with it, In other words, all the energy and power on the earth come from the sun. Once the sun is short, it is bound to harm the earth. Before the 1930s, people always thought that the sun would burn out one day and turn from white to orange and then red, In the 1930s, when physicists learned the mystery of the sun's glow and heat, the situation was very different. It turned out that the sun's energy came from its thermonuclear reaction, The life of the sun will go through the stages of gravitational contraction, main sequence star, red giant and compact star. The main sequence star stage is the stable stage of the sun. This stage will last for 10 billion years. At present, the sun only spends half of its time and is in the middle age. Once the sun reaches the stage of red giant, the end of the earth will come, This will happen billions of years later. Apart from the sun's interference with the earth, are there any other factors? Some scientists believe that the sun may have a brother, a companion star of the sun, which keeps circling the sun day and night. Every 26 million years, it will turn to the nearest place to the sun to "make waves" and its strong gravity will cause great disturbance to many comets, There are 1 billion comets in the solar system. Due to the collision, the earth and other planets will become the "target" of these comets. If the mass of the comet colliding with the earth is large enough, the consequences will be unimaginable: the light ones will die out, and the ecology will change dramatically; the heavy ones will fall apart, and the earth will be "shattered". However, this sun companion, which may bring accidents to the earth, has not been found, But many scientists believe it exists

How many zinc particles are needed to produce 6G hydrogen with 10% impurity zinc and 100g dilute sulfuric acid

So: (65g * 3) * (10 / 9) = 216.7g. In other words, sulfuric acid is less 100g dilute sulfuric acid is obviously not enough I will not pursue it It's better to check with the teacher

The circumference of the bottom surface of a cylinder is equal to the height. If the height is increased by 4cm, the surface area of the cylinder will be increased by 62.8cm2. Find the volume of the cylinder
The equation is OK, please solve it

Let the height be x and the perimeter of the bottom be X
x(x+4) - x×x = 62.8
4x = 62.8
x = 15.7
Bottom radius = 15.7 / 2 π = 2.5 cm
Volume = π (2.5) ^ 2 × 15.7 = 308.1125 CC