Question

Поезд отправился со станции в 16 ч со скоростью 54 км/ч. в 19 ч в противоположном направлении отправился второй поезд.В 24ч расстояние между ними было равно 642 км. С какой скоростью двигался второй поезд?

Answer 1

1) 19 - 16 = 3 (ч) - ехал первый поезд до отправления второго
2) 3 * 54 = 162 (км) - проехал первый поезд до отправления второго
3) 642 - 162 = 480 (км) - проехали оба поезда после 19 ч
4) 24 - 19 = 5 (ч) - ехали поезда после 19 ч
5) 480 : 5 = 96 (км/ч) - скорость отдаления поездов
6) 96 - 54 = 42 (км/ч) - скорость второго поезда

Ответ: 42 км/ч

Answer 2

Problem Analysis

We are given that a train departs from a station at 16:00 with a speed of 54 km/h. At 19:00, a second train departs from the same station in the opposite direction. At 24:00, the distance between the two trains is 642 km. We need to determine the speed of the second train.

Solution

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

From 16:00 to 19:00, the first train travels for 3 hours at a speed of 54 km/h. Therefore, the distance covered by the first train during this time is 3 * 54 = 162 km.

From 19:00 to 24:00, the first train travels for 5 hours at a speed of 54 km/h. Therefore, the distance covered by the first train during this time is 5 * 54 = 270 km.

Let's denote the distance covered by the second train from 19:00 to 24:00 as d km.

According to the problem, at 24:00, the distance between the two trains is 642 km. Therefore, we can write the following equation:

162 + 270 + d = 642

Simplifying the equation, we get:

432 + d = 642

Subtracting 432 from both sides, we get:

d = 642 - 432 = 210 km

Therefore, the distance covered by the second train from 19:00 to 24:00 is 210 km.

Now, we can calculate the speed of the second train by dividing the distance covered by the time taken:

Speed = Distance / Time = 210 km / 5 hours = 42 km/h

Therefore, the speed of the second train is 42 km/h.

Answer

The second train was moving at a speed of 42 km/h.