What projection and coordinate system does Google China map use

What projection and coordinate system does Google China map use

Mercator projection
In foreign countries, it is WGS84 coordinate system. In China, some maps are WGS84 coordinate system and some maps are Mars coordinate system (gjc-02)

If the number ratio of a and B teams is 3:4, and the number ratio of a and C teams is 5:3, what is the number ratio of the three teams?

The number of team a is x, B, y, C, Z
10: Y = 3:4, so y = 4x / 3
10: Z = 5 / 2: 3 = 5:6, so z = 6x / 5
X:Y:Z=X:4/3X:5/6=1:4/3:6/5=15/15:20/15:18/15=15:20:18

N natural numbers (1,2,...) are known N) The total number of each digit is 2004, find n
For example, there are natural numbers 1,2,3 When the total number of digits is 11, n = 10}

You can enumerate analysis:
1. There are 9 numbers from 1 to 9
2. 10 ~ 99, 90 * 2 = 180 digits in total
2004-180-9 = 1815 numbers
1815 / 3 = 605, the number is 100-604
So n = 604

The distance between AB and B is 80km. A bus starts from a to B. two hours later, a car starts from a in the same direction. The speed of the car is three times that of the bus. As a result, the car arrives at B 40 minutes earlier than the bus

The minute hand on the clock face turns 180 degrees, and the hour hand turns () degrees. A, 180 B, 90 C, 30 d, 15 D

The minute hand on the clock face turns 180 degrees, and the hour hand turns (d) degrees. A, 180 B, 90 C, 30 d, 15 D

The total length of Shanghai Nanjing Expressway is 274.08 km. A car and a bus leave Shanghai and Nanjing at the same time. The car travels 118.44 km per hour on average and the bus 110 km per hour on average. After a few hours, the two cars meet on the way?

1.2

Given a ^ 2n = 2, find the value of (2a ^ 3n) ^ 2-4a ^ n + 1 × (- A ^ n-1)

40
This is the variant
（2a^3n）^2 = 4a^6n
4a^(n+1)×（－a^n-1）=4a^2n
Original formula = 4A ^ 6N + 4A ^ 2n = 4A ^ 2n (a ^ 4N + 1)

The speed of the train is 168 kilometers per hour, which is 6 kilometers more than twice the speed before the speed increase. How many kilometers per hour does the train travel before the speed increase? (solution of a series of equations)

Suppose the train travels x kilometers per hour before the speed increase. According to the meaning of the question, we get 2x + 6 = 168 & nbsp; 2x = 168-6 & nbsp; & nbsp; X = 162 △ 2 & nbsp; & nbsp; & nbsp; X = 81 A: the train travels 81 kilometers per hour before the speed increase

If (m-1) x ^ (m ^ 2) * y is a quadratic monomial about X, y, then M=_____ And its coefficient is______

m^2=1,m-10
The solution is m = - 1, coefficient = - 2

A lot of sand and cement are transported into a construction site, and the number of sand bags is twice that of cement. 30 bags of cement and 40 bags of sand are used every day. After a few days, all cement is used up, and 120 Bags of sand are left. How many bags of sand and cement are there?

The number of days when cement is used up: 120 (30 × 2-40), = 120 (20), = 6 (days); the total number of bags of cement: 30 × 6 = 180 (bags); the total number of bags of sand: 180 × 2 = 360 (bags); a: 180 bags of cement and 360 bags of sand