There are two trains running from a and B at the same time. The slow train runs 70 kilometers per hour, and the fast train runs 10 kilometers more than the slow train. After four hours, the two trains run 23 times of the whole journey. On the railway diagram with the scale of 1:10000000, what is the distance between a and B in the diagram?

The speed of express train is 70 + 10 = 80 (km \ \ h), the distance of two trains: (70 + 80) × 4 = 600 (km), 600 ／ 23 = 900 (km); 900 km = 90 million cm, 90 million × 110 million = 9 (CM); a: the distance between a and B is 9 cm

The average of the three numbers is 8.4, and two of them are the same. They are all 9.6. What is the third number

The average of the three numbers is 8.4, and two of them are the same, 9.6,
The third number = 8.4x3 - 9.6 - 9.6 = 6
Wuliangshou Buddha, the Buddha said that the sea of bitterness is endless, looking back is the shore!
Almsgiver, I see that you are a unique talent in the Wulin
If I devote myself to practice, I will become a great tool in the future. I just have a book in my hand, which I want to give to the benefactor
I have a little test, please click next to the answer

It's an even number. It's a multiple of 2 and 3. It's a two digit number. After you exchange the position with the number on the ten digit number, it's a multiple of 5. How do you write it?

[2,3]＝6
Such a two digit ten digit number can only be a multiple of 5, while the two digit ten digit number can only be a multiple of 5 and the ten digit number can only be a multiple of 6
The two digit number is 54

A number consists of two 10, three 0.1 and eight 0.001. What is the number?

A number consists of two 10, three 0.1 and eight 0.001, which is (20.308)
If you don't understand, please ask

On the map with a scale of 1:6000000, the distance between a and B is 20.4cm. It is 8 hours since a and B meet each other

Is the speed 80 km / h, the speed of car B?
Actual distance = 20.4 * 6000000 = 122400000 cm = 1224km
Two vehicle speed sum = 1224 △ 8 = 153 km / h
Vehicle B speed = 153-80 = 73 km / h

There is a quadrilateral land ABCD (as shown in the figure), ∠ B = 90 °, ab = 4m, BC = 3M, CD = 12M, Da = 13m?

Connect AC. ∵ ∠ B = 90 °, AC = AB2 + BC2 = 5. ∵ 52 + 122 = 132, ∵ △ ADC is right triangle. S quadrilateral ABCD = 12 × 3 × 4 + 12 × 12 × 5 = 36m2

There are three piles of coal, a, B and C. If a and B are piled together, it is four times the weight of C. if B and C are piled together
The total amount is three times that of A. how much is the weight of a?

A + B = 4 / 5, C = 1-4 / 5 = 1 / 5
B + C = 3 / 4, a = 1-3 / 4 = 1 / 4
B = 1-1 / 5-1 / 4 = 1-9 / 20 = 11 / 20
A: B = 1 / 4:11 / 20 = 5:11
A is 5 / 11 of B

Given that the inequality a (x) square + (A-1) x + A-1 is less than 0, it holds for all real numbers x, and the value range of a is obtained

For Ax & # 178; + (A-1) x + A-1

A and B leave from ab 385km apart at the same time. After 3.5 hours, the two vehicles meet. It is known that B travels 60km per hour,
Note that there are two ways to solve the equation

A: suppose the speed of car a is x, then the sum of the two speeds is x + 60. According to the topic meaning: (x + 60) × 3.5 = 385x + 60 = 110x = 50, so: the speed of car a is 50 km / h. suppose that car a has driven y km / h, then car B has driven 385-y km / h. according to the topic meaning: 385-y = 60 × 3.5385-y = 210y = 175, so: the speed of car a = Y / 3

Solving inequality 4x-x ^ 2-4 > = 0

Double - 1
x²-4x+4