![](data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" viewBox="0 0 72 71" width="72"></svg>)
The two trains run in opposite directions from 120km away. The speed of a is 84km / h, and that of B is 60km / h How long does it take for the two cars to be 24km apart
Let's say that after X hours, it is 24 km away from each other after meeting
84X+60X=120+24
144X=144
X=1
A: after one hour, the distance between the two cars is 24km
How to solve the equation of 5.2x = 26?
x=26/5.2
x=5
From Liuzhou to Beihai, they meet 480 kilometers away. There are two trains running from the two places at the same time. After five hours, they meet, and a and B are very happy
The speed of the two cars is 7:5. What's the speed of the two cars?
[7 + 5] * = 480 / 5 is equivalent to [480 divided by 5] divided by [7 + 5] = (that is, x)
Multiply X by 7 and 5
A 56 B 40
What the people above said is wrong
==So - 1 unit speed = 96 / 12 = 8 km / h
This can't be 1 unit speed, there's no such explanation in mathematics!
96 km / h is the common one hour journey of Party A and Party B
Move the decimal point of a decimal one place to the right to get a new number, and the new number is 25.2 more than the original number. How much is the new number
Move the decimal point of a decimal one place to the right, and the number will be expanded 10 times
So the original number is 25.2 (10-1) = 2.8
The new number is 2.8 * 10 = 28
The speed of a car is 47 times that of a train. Two cars are running from two places at the same time, and they meet at a distance of 15 kilometers from the midpoint. How many kilometers does the train travel?
The distance of the whole journey: 15 △ 74 + 7-12, = 15 △ 322, = 110 (km), the distance of the train: 110 × 711 = 70 (km). A: at this time, the train runs 70 km
In the triangle ABC, if acosb + bcosc + ccosa = bcosa + ccosb + acosc, we find the shape of the triangle?
In the triangle ABC, if acosb + bcosc + ccosa = bcosa + ccosb + acosc, we find the shape of the triangle?
The equation deformation is (A-C) CoSb + (B-A) COSC + (C-B) cosa = 0. Because cosa is a = cos [π - (B + C)] = - cos (B + C) (B + C)] = - cos (B + C) = sinbssinc-cosb COSC, a = [BB + cc-2bbccosa] = [BB + cc-2bc-2bcc-2bc (sinbssinsinc-coscoscosb COSC, a = 0. Because cosa is a = cos [cos [π - (B + B + B + B + cc-2bc-2bc (sinbssinbssinbcsinc-coscoscoscosbcc) - cosb-cosb-cosb-cosb + (b-cosb + (B - (B - [BB + CC + cc-cc-2b-2bbcbcbcbcbcbcbcbcbcsinbssinbssinbssinbssinbssinbcsinbcsinsinc-c-c-c-c-coscoscoscoscosb bcosc) = 0
Later
The length of train a and train B are 144m and 180m, and train a runs 4m more per second than train B. the two trains are facing each other, and it takes 9s from meeting to staggering. What's the speed of the two trains?
Suppose car B travels XM per second, then car a Travels (x + 4) m per second. According to the meaning of the question, we get: 9 (x + X + 4) = 144 + 180, sort out: 2x = 32, solve: x = 16, then car a travels 20m per second, car B travels 16m per second
The average number of the five numbers is 40. The average number of the first three numbers is 45, and the average number of the last three numbers is 30. What's the number in the middle?
Sum of the first three numbers = 45 * 3 = 135
Sum of the last two numbers = 40 * 5-135 = 65
Sum of the last three numbers = 30 * 3 = 90
So the middle = 90-65 = 25
Hope to help you_ ∩)O~
When they set out, their speed ratio was 3:2. After their first meeting, a's speed increased by 20%, and B's speed increased by 30%. In this way, when a arrives at B, B is still 14 kilometers away from a, so how many kilometers is the distance between a and B?
Suppose the distance between a and B is SKM, and the speed of a and B is 3x and 2x respectively. When a and B meet for the first time, the distance they take is 3s5 = 0.6skm and 2s5 = 0.4skm respectively. According to the time series equation of a to B after meeting: 0.4s3x (1 + 20%) = 0.6s − 142x (1 + 30%), s = 45km. A: the distance between a and B is 45km
Using mathematical induction to prove the inner angle sum of convex n-polygon f (n) = (n-2) 180 ° (n ≥ 3)
Using mathematical induction to prove the inner angle sum of convex n-polygon f (n) = (n-2) 180 ° (n ≥ 3)
When n = K + 1, I don't know
Proof: obviously, because the least number of sides in a polygon is a triangle, and the number of sides of a polygon is n, then n ≥ 3. So the title can be translated as "the sum of the interior angles of a convex n-sided shape (n ≥ 3) is equal to 180o (n-2)". Step 1: when n = 3, a convex n-sided shape is a triangle
RELATED INFORMATIONS
- 1. On the map with a scale of 1:3000000, it is measured that the distance between a and B is 3.6cm. How many hours can a car arrive from a tunnel B at a speed of 60km per hour?
- 2. On the Shanghai Nanjing Expressway, a car was driving at a constant speed of 108km / h. The driver suddenly found that there was an emergency ahead. After 0.6s, he began to brake, and after 4.4S, he taxied 52m, and the car stopped. The average speed of the driver from finding the situation to stopping was______ ．
- 3. There are 60 employees in a company, including 28 male employees. What is the proportion of male employees in the total number of the company? What is the proportion of female employees in the total number of the company What's the percentage of male employees and female employees?
- 4. One eighth of a is equal to one ninth of B. the ratio of a to B is ()
- 5. Second grade math problem 3_ 3_ 3_ 3=1,3_ 3_ 3_ 3=2,3_ 3_ 3_ 3 = 3 fill in + or - in the underline to make the equation true!
- 6. When a car goes from city a to city B, it takes two fifths of the whole journey in three hours. According to this calculation, how many parts of the whole journey are left after another four hours?
- 7. If a and B are opposite to each other, C and D are reciprocal to each other, and the absolute value of M is 2, find the value of 2 | m | a | B | CD
- 8. It is known that the function f (x) is an even function defined on R. when x ≥ 0, f (x) = (12) x (1) draw the image of the function f (x); (2) write the monotone interval of F (x) according to the image, and write the value range of the function
- 9. Which is colder, zero degree water or zero degree ice? Zero degree ice melts into zero degree water to absorb heat. Why doesn't the temperature rise? How does energy transform in this process?
- 10. At least 1024 minus how much is a multiple of three
- 11. Mathematical problems in mathematics A water conservancy survey team walked 5.3km upstream for the first time, 5.3km upstream the next day, 15km downstream the third day, and 5km downstream the fourth day. Where is the starting point of the survey team? How many kilometers away from the starting point?)
- 12. If the electron ant P starts from point B and moves to the left at the speed of 6 unit length / s, and the other electron ant Q starts from point a and moves to the left at the speed of 4 unit length / s, let two electron ants meet at point D on the number axis. Do you know the number of point d?
- 13. How many kilos is a kilo? How many grams is a kilo? How many kilos is a ton!
- 14. Why is it that electric energy is converted into chemical energy when a battery is charged? Why is it that when a battery is charged, electrical energy is converted into chemical energy, while when a battery is used, chemical energy is converted into electrical energy?
- 15. Two resistors are connected in parallel. It is known that R1 is equal to 30 ohm, I1 is equal to 2 A, R2 is equal to 4 ohm. Calculate the total voltage and total current
- 16. 20 festival lanterns form a series circuit, which is connected to the home circuit. What is the voltage at both ends of each lantern?
- 17. Let vectors A1, A2,. As (s > = 2) be linearly independent, and β 1 = a1 + A2, β 2 = A2 + a3,... β S-1 = a (s-1) + as, BS = as + A1. The linear correlation of vectors β 1, β 2,. β s is discussed,
- 18. Calculation: (1,4 / 5) - 5 / 6 + 7 / 10-8 / 15) times (- 30) To process! To be 100% right!
- 19. (1+1/3+1/5+1/10+1/15+1/30)/(1/2+1/4+1/6+1/12+1/20+1/60)=? Simple calculation
- 20. Simple calculation of 5 / 11 × 6 / 17 + 5 / 17