Question

Из одного города в другой выехал поезд.Первую половину расстояния он проехал за 2,4 часа со скоростью 72,75км/ч, а вторую половину -за 3,6 км/ч. Найдите среднюю скорость поезда?

Answer 1

РЕШЕНИЕ
1) s = 72.75 * 2.4 = 174.6 км - половина пути
2) S = 2*s = 174.6*2 = 349.2 км - весь путь
3) Т = 2,4 + 3,6 = 6 ч - всё время в пути
4) V ср = S : T = 349.2 : 6 = 58.2 км/ч - средняя скорость - ОТВЕТ

Answer 2

Calculation of Average Speed

To find the average speed of the train, we need to calculate the total distance traveled and the total time taken.

Let's assume the total distance traveled by the train is D.

According to the given information, the train traveled the first half of the distance at a speed of 72.75 km/h for 2.4 hours, and the second half of the distance at a speed of 3.6 km/h for 3.6 hours.

The time taken to travel the first half of the distance is 2.4 hours, and the time taken to travel the second half of the distance is 3.6 hours.

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

D = 2 * (First Half Distance)

The first half distance can be calculated using the formula:

First Half Distance = Speed * Time

Substituting the given values:

First Half Distance = 72.75 km/h * 2.4 hours

Similarly, the second half distance can be calculated using the formula:

Second Half Distance = Speed * Time

Substituting the given values:

Second Half Distance = 3.6 km/h * 3.6 hours

Now, we can calculate the total distance:

D = 2 * (First Half Distance + Second Half Distance)

Once we have the total distance, we can calculate the average speed using the formula:

Average Speed = Total Distance / Total Time

Substituting the given values:

Average Speed = D / (2.4 hours + 3.6 hours)

Let's calculate the average speed step by step.

Calculation Steps:

1. Calculate the first half distance: - First Half Distance = 72.75 km/h * 2.4 hours

2. Calculate the second half distance: - Second Half Distance = 3.6 km/h * 3.6 hours

3. Calculate the total distance: - D = 2 * (First Half Distance + Second Half Distance)

4. Calculate the average speed: - Average Speed = D / (2.4 hours + 3.6 hours)

Let's perform the calculations:

1. Calculate the first half distance: - First Half Distance = 72.75 km/h * 2.4 hours = 174.6 km

2. Calculate the second half distance: - Second Half Distance = 3.6 km/h * 3.6 hours = 12.96 km

3. Calculate the total distance: - D = 2 * (First Half Distance + Second Half Distance) = 2 * (174.6 km + 12.96 km) = 375.12 km

4. Calculate the average speed: - Average Speed = D / (2.4 hours + 3.6 hours) = 375.12 km / 6 hours = 62.52 km/h

Therefore, the average speed of the train is 62.52 km/h.