Question

Первые три четвертных пути поезд шёл со скоростью 80 км /ч , в остальной участок пути со скоростью 40 км/ч какова средняя скорость движения поезда на всём пути

Answer 1

(80+80+80+40)/4=70
Это легко)

Answer 2

Calculation of Average Speed

To calculate the average speed of the train for the entire journey, we need to consider the distances traveled at different speeds.

Let's assume that the first three-quarters of the journey were traveled at a speed of 80 km/h, and the remaining distance was traveled at a speed of 40 km/h.

To calculate the average speed, we can use the formula:

Average Speed = Total Distance / Total Time

Since we don't have information about the distances traveled at each speed, we cannot calculate the exact average speed. However, we can provide an example calculation based on the given information.

Let's assume that the total distance of the journey is 240 km (3/4 of the journey at 80 km/h and 1/4 of the journey at 40 km/h).

The time taken to travel the first three-quarters of the journey at 80 km/h can be calculated as:

Time = Distance / Speed = (3/4) * 240 km / 80 km/h = 9/4 hours

The time taken to travel the remaining distance at 40 km/h can be calculated as:

Time = Distance / Speed = (1/4) * 240 km / 40 km/h = 3/4 hours

Therefore, the total time taken for the entire journey is:

Total Time = (9/4) hours + (3/4) hours = 12/4 hours = 3 hours

Now, we can calculate the average speed using the formula:

Average Speed = Total Distance / Total Time = 240 km / 3 hours = 80 km/h

Based on the given information and the example calculation, the average speed of the train for the entire journey is 80 km/h.

Please note that this calculation is based on assumptions made due to the lack of specific information about the distances traveled at each speed. The actual average speed may vary depending on the actual distances traveled at different speeds.