Question

Решите задачу Из двух городов, расстояние между которыми 520 км, одновременно вышли на встречу друг другу два поезда и встретились через 4 часа. Один поезд шел со средний скоростью 60 км/ч. С какой скоростью шел другой поезд?

Answer 1

1. 60 * 4 = 240 (км) - прошёл 1 поезд ; 

2. 520 - 240 = 280 (км) - прошел 2 поезд ; 

3. 280 : 4 = 70 (км/ч) - скорость другого поезда . 

Ответ : Поезд шёл со скоростью 70 км/ч . 

Answer 2

Problem Analysis

We are given that two trains start simultaneously from two cities that are 520 km apart and meet each other after 4 hours. One train is traveling at an average speed of 60 km/h. We need to find the speed of the other train.

Solution

Let's assume the speed of the other train is x km/h.

We know that the distance traveled by the first train is equal to the distance traveled by the second train, as they meet each other. Therefore, we can write the equation:

Distance traveled by the first train = Distance traveled by the second train

Using the formula distance = speed × time, we can calculate the distances traveled by each train.

For the first train: Distance = Speed × Time = 60 km/h × 4 hours = 240 km

For the second train: Distance = Speed × Time = x km/h × 4 hours = 4x km

Since the distances are equal, we can set up the equation:

240 km = 4x km

Now we can solve for x to find the speed of the second train.

Calculation

240 km = 4x km

Dividing both sides of the equation by 4: 240 km / 4 = 4x km / 4 60 km = x km

Therefore, the speed of the second train is 60 km/h.

Answer

The second train was traveling at a speed of 60 km/h.