The city youth library has 960 science and technology books and 1800 literature and art books, and now plans to purchase 60 science and technology books and 160 literature and art books every month A few months later, the literature and art books are twice as many as the science and technology books

The city youth library has 960 science and technology books and 1800 literature and art books, and now plans to purchase 60 science and technology books and 160 literature and art books every month A few months later, the literature and art books are twice as many as the science and technology books

Suppose that after x months, literature books are twice as many as science and technology books, then
2（960+60x）=1800+160x
The solution is three months

There are 40 science and technology books in the library, 10 more than literature and art books, and ()% less than literature and art books

There are 40 science and technology books in the library, 10 more than literature and art books, and 20% less than literature and art books
10 ÷ (40 + 10) = 20%

The library bought five boxes of books, a total of 300, which were divided into 12 classes on average. How many books were assigned to each class?

300 / 12 = 12 = 25
5 / 12 = 5 / 12 (case)
A: each class is divided into 25 books, and each class is divided into 5 out of 12 boxes

About the construction of the library, good plus 100 points
In order to improve children's spare time, please build a book corner. Please write a proposal

Dear president
Hello!
I am a student in class xx. In six years of study and life, the school and teachers have given us meticulous care and education, which has made us grow up from a child who is not sensible to a qualified primary school graduate. Now, we are going to leave the school, leaving everything there. I am really reluctant to part with it
Now, our school is developing very well. There are all kinds of computer rooms, nature rooms and voice rooms. It has become a school with complete facilities. The teachers are also selected carefully. Therefore, everyone is very relaxed and happy here. However, as a school and a teacher, the work will not be perfect
1. Send more people to manage the stairway, especially when raising the flag and doing exercises, so as to maintain the order and prevent the corridor from being crowded and blocked. If you can, stagger the time when people go up and down the stairs, so that those upstairs will go down first, and those downstairs will go back after they finish. In this way, the corridor will be much more relaxed, and accidents are not easy to occur
2. Take English class and art class to the speech room and art room. Don't leave them empty. Install the computer in the classroom as soon as possible, so that the teacher can show the relevant information more vividly and vividly
3. Resume the activity of "life practice week", let the students learn to take care of themselves and get along well with others. We can also take you to military training, let us experience the difficulties, exercise our body and temper our will
Shoot two hawks with one arrow love. 4. open the library. Students who want to borrow books can apply for "library card". In the library, they can add several administrators to check and supervise their reading. They can also investigate what kind of books they like and buy some ones back in their classmates. This widens our field of vision, and cultivates our awareness of love books, books and discipline, which is killing two birds with one stone.
5. Open more courses in physical education class, such as playing football, basketball, table tennis, etc., which can let us master more skills, plus long-term exercise, our health will be better
Dear headmaster, in order to let us grow and live better, please accept my suggestions!

Three LEDs in parallel, 12V power supply series how much resistance?

Must parallel connection be necessary? Series connection is more efficient and can handle lines better

F (x) = 2x + √ (X & # 178; + 2x + 1) is expressed as a piecewise function

∵f(x)=2x+√(x²+2x+1)=2x+√(x+1)²=2x+|x+1|
∴f(x)=3x+1,x>-1
x-1,x≤-1

Which one consumes more power, a 100 watt energy-saving lamp or a 60 watt incandescent lamp
My family has a 60 watt incandescent lamp and a 100 watt energy-saving lamp. They are all on for a long time. I don't know which one is more energy-saving. Please help me, great Xia!

If the power of 100W and 60W is power, then the power saving of 60W is obvious
But if it is the wattage of energy-saving lamp and lighting wattage, then there is the following formula: wattage of energy-saving lamp = wattage of incandescent lamp * 0.2, so it is energy-saving lamp
Because energy saving lamps can save more than 80% of electricity. For details, please see the link I gave you, the knowledge of electronic energy saving lamps
Energy saving lamps can well convert electric energy into light energy, only a small part of which is converted into heat energy. Moreover, energy saving lamps have long service life, good for eyes, white light, and look comfortable. Therefore, it is suggested that energy saving lamps should be replaced at home as far as possible to make some contribution to saving national resources

Computer network principle calculation topic
In the 1200 BPS asynchronous transfer protocol communication adapter, the effective transfer rate of 7-bit data, 1-bit check bit and 1-bit stop bit is calculated. What is the meaning of 7 + 1 + 1 + 1 in the answer

7 is the data bit and 3 1s are the check bit start bit and stop bit

Two lamps marked with 220 V 40 W and 220 V 100 W are connected in series on the 220 V circuit. It is found that the luminous intensity of the two lamps is darker than that when they are connected to the same circuit
a. The rated current of the bulb is reduced B. the rated power is reduced C. the rated voltage is reduced D. the voltage of both ends of the bulb is lower than the rated voltage

Should choose D, because two lamps in series, has the function of partial voltage, the sum of two lamp voltage is 220 V, the voltage of each lamp is lower than 220 v

How to calculate 11 / 15-15 / 11 × 1 / 6

11 △ 15-15 / 11 × 1 / 6
=11/15-11/15x1/6
=11/15x(1-1/6)
=11/15x5/6
=11/18
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