Question

Первую четверть своего пути поезд прошел со скоростью 70 км в час. С какой средней скоростью двигался поезд на оставшейся части пути если средняя скорость поезда на всем пути равна 50 км в час. (45,7) Скорость поезда на подъеме равна 40км/ч, а на спуске 80 км/ч. Определите среднюю скорость поезда на всем участке пути, если спуск в 3 раза длиннее поъема. (64км/ч) В скобках ответы

Answer 1

70-50=20(кл)
Ответ: 20 километров

Answer 2

Calculation of Average Speed

To calculate the average speed of the train on the remaining part of the journey, we can use the formula:

Average Speed = Total Distance / Total Time

We know that the train traveled the first quarter of the journey at a speed of 70 km/h and the average speed for the entire journey is 50 km/h. Let's assume the total distance of the journey is D.

The time taken for the first quarter of the journey can be calculated using the formula:

Time = Distance / Speed

For the first quarter, the time taken is:

Time1 = D / 4 / 70

The remaining distance for the journey is:

Remaining Distance = D - D / 4

The time taken for the remaining part of the journey can be calculated using the formula:

Time2 = Remaining Distance / Average Speed

Now we can calculate the average speed for the remaining part of the journey:

Average Speed = Remaining Distance / Time2

Let's substitute the values and calculate the average speed:

Average Speed = (D - D / 4) / ((D - D / 4) / 50)

Simplifying the equation:

Average Speed = 50

Therefore, the average speed of the train on the remaining part of the journey is 50 km/h.