Question

Пассажирский поезд ,двигаясь со скорость 90 км /ч за ,3 часа проходит 75% расстояния между городами . Какова средняя скорость пассажирского поезда ,если весь путь между этими городами он проходит за 4,5 ч ? Найдите среднюю скорость товарного поезда ,если этот же путь занимает у него 6 ч ?

Answer 1

1) 80км/ч - если весь путь за 4,5ч
2) 60км/ч - если весь путь за 6ч

Answer 2

Calculation of Average Speed for the Passenger Train

To calculate the average speed of the passenger train, we can use the formula:

Average Speed = Total Distance / Total Time

Given that the passenger train travels at a speed of 90 km/h for 3 hours and covers 75% of the distance between the cities, we need to find the total distance and total time.

Let's assume the total distance between the cities is represented by D.

The passenger train covers 75% of the distance, which is equal to 0.75D.

The time taken to cover this distance is 3 hours.

To find the total distance, we can use the equation:

0.75D = 90 km/h * 3 hours

Simplifying the equation, we get:

0.75D = 270 km/h

Dividing both sides of the equation by 0.75, we find:

D = 360 km

Now that we know the total distance, we can calculate the total time taken to cover the entire distance.

The passenger train covers the entire distance of 360 km in 4.5 hours.

Using the formula for average speed, we have:

Average Speed = Total Distance / Total Time

Average Speed = 360 km / 4.5 hours

Simplifying the equation, we find:

Average Speed = 80 km/h

Therefore, the average speed of the passenger train for the entire journey is 80 km/h.

Calculation of Average Speed for the Freight Train

To calculate the average speed of the freight train, we can use the same formula:

Average Speed = Total Distance / Total Time

Given that the freight train takes 6 hours to cover the same distance between the cities, we can calculate the average speed.

Using the formula for average speed, we have:

Average Speed = Total Distance / Total Time

Average Speed = 360 km / 6 hours

Simplifying the equation, we find:

Average Speed = 60 km/h

Therefore, the average speed of the freight train for the entire journey is 60 km/h.

Please note that these calculations assume a constant speed throughout the journey and do not account for any stops or variations in speed.