According to media reports, the total number of Chinese outbound tourists in 2009 was about 50 million, and that in 2011 was about 72 million. If the total number of Chinese outbound tourists increased year by year in 2010 and 2011, please answer the following questions: (1) the average annual growth rate of the total number of Chinese outbound tourists in the past two years; (2) if the average annual growth rate remains the same in 2012 Can you predict the total number of Chinese outbound tourists in 2012?

According to media reports, the total number of Chinese outbound tourists in 2009 was about 50 million, and that in 2011 was about 72 million. If the total number of Chinese outbound tourists increased year by year in 2010 and 2011, please answer the following questions: (1) the average annual growth rate of the total number of Chinese outbound tourists in the past two years; (2) if the average annual growth rate remains the same in 2012 Can you predict the total number of Chinese outbound tourists in 2012?

(1) Suppose that the annual average growth rate of the total number of Chinese outbound tourists in the past two years is X. according to the meaning of the question: 5000 (1 + x) 2 = 7200, the solution is X1 = 0.2 = 20%, X2 = - 2.2 (2) if the annual average growth rate remains the same in 2012, the total number of Chinese outbound tourists in 2012 will be 7200 (1 + x) = 7200 × (1 + 20%) = 86.4 million person times. A: it is predicted that the total number of Chinese outbound tourists in 2012 will be about 86.4 million person times

The ticket price regulations of children's Park are as follows: ticket number: 1-50 people: 51-100 people: ticket price: 13 yuan per person for more than 100 people: 11 yuan per person; A total of 104 students from Class A and class B of Grade 7 of a school went to the children's Park. The number of students in class A was less than 50, while the number of students in class B was more than 50. If the two classes bought tickets separately, they would have to pay a total of 1240 yuan? (2) How much money can you save if you buy tickets as a group?

(1) Suppose there are X students in class A, then there are (104-x) students in class B. according to the meaning of the question, we get: 13X + 11 (104-x) = 1240, and the solution is: x = 48104-x = 104-48 = 56. Answer: there are 48 students in class A and 56 students in class B. (2) according to the meaning of the question, we get: 1240-9 × 104 = 304 (yuan). Answer: if two classes buy tickets together as a group, we can save 304 yuan

During the training, all the members of a cycling team were moving forward at the speed of 35km / h. suddenly, member 1 was moving alone at the speed of 45km / h. After 20km, he turned around and rode back at the speed of 45km / h until he met with other members. How long did it take for No. 1 to leave the team and rejoin the team?

Solution 1: the time for team member 1 to travel to 20 km: 20 / 45 = 4 / 9 hours, the distance for other team members to travel is 35 * 4 / 9 = 140 / 9 kilometers, the distance between other team members and team member 1 is: 20-140 / 9 = 40 / 9 kilometers, the time for meeting: 40 / 9 / (35 + 45) = 1 / 18 hours, the shared time is: 1 / 18 + 2 / 9 =

Maximum power of household meter
What is the maximum load of 40A and 60A meters

The maximum load of 40A meter is 8800w, and that of 60A meter is 13200w

It is known that M is an integer, and the system of equations 4x − 3Y = 66x + my = 26 has an integer solution, then the value of M is______ ．

4x − 3Y = 6, ① 6x + my = 26, ② × 2 - ① × 3, we get: (2m + 9) y = 34, the solution is y = 342m + 9, substituting y = 342m + 9 into ①, we get: x = 14 (1022m + 9 + 6) = 3M + 392m + 9, ∵ the system of equations has integer solution, ∵ 2m + 9 = - 1, - 2, - 17, 1, 2, 17, the solution is m = - 5, - 5.5, - 13, - 4, - 3.5, 4

Given the different current of the motor when it is stationary and rotating, the mechanical efficiency and the efficiency of electrical energy converted into mechanical energy are expressed by letters
Given the different current of the motor when it is stationary and rotating, the mechanical efficiency and the efficiency of electrical energy converted into mechanical energy are all represented by letter symbols

When the motor is stationary, the current is I1; when the motor is rotating, the current is I2, and the resistance of the motor coil is r
When the motor is not moving, all the consumed electric energy is converted into the heat (internal energy) generated by the coil, which is the voltage in the pure resistance circuit
U=I1*R
When the motor rotates, part of the electric energy is converted into internal energy and part into mechanical energy
Electricity consumed
W=UIt=I1*R*I2*t
The electric energy converted into internal energy is
W1=(I2)^2 R t
The electrical energy converted into mechanical energy is
W2=W-W1=I1*R*I2*t - (I2)^2*R*t=(I1 - I2)I2*R*t
The efficiency of converting electrical energy into mechanical energy
n=W2/W=(I1 - I2)I2*R*t / I1*R*I2*t = (I1 - I2) / I1

Given X & # 178; y + 2XY & # 178; = 2, find the value of (X & # 178; y-2xy & # 178;) + (X & # 178; y + 6xy & # 178;)

x²y=2-2xy²
（2-2xy²-2xy²）+（2-2xy²+6xy²）
=（2-4xy²）+（2+4xy²）
=4
OK, give me points!

Two lamps marked with "220 V, 110 W" are connected in series to the lighting circuit. The total power consumed by the two lamps is w. if the two lamps are connected in parallel, the total power of the two lamps is w
Seeking positive solution

Two lamps marked with "220 V, 110 W" are connected in series to the lighting circuit. The total power consumed by the two lamps is 50 W. if they are connected in parallel, the total power of the two lamps is 200 W

Factorization: (1) 2x (a-b) - (B-A) (2) 3a2-27 (3) - 4a2x2 + 8ax-4 (4) 9 (2a + 3b) 2-4 (3a-2b) 2

The following statement about the relationship between current, voltage and resistance is correct ()
A. The current in the circuit with high voltage must be large. B. the current in the circuit with high resistance must be small. C. The current in the conductor has nothing to do with voltage and resistance. D. the resistance in the conductor has nothing to do with current and voltage

A. Only when the resistance is constant, the current in the circuit with high voltage must be large, so a is wrong; B, only when the voltage is constant, the current in the circuit with high resistance must be small, so B is wrong; C, the current in the conductor is related to the voltage and resistance, so C is wrong; D, the conductor resistance is determined by the conductor material, length and cross-sectional area, and has nothing to do with the voltage and current of the conductor, so D Correct. So D