Question

Поезд прошел путь в 210 км сначала со скоростью 60км/ч, а затем из-за аварийного участка он снизил скорость до 20 км/ч. Весь путь был пройден за 6ч. Найдите длину аварийного участка пути.

Answer 1

210/60=3,5 часов
6-3,5=2,5 часов (аварийный участок)
2,5*20=50 км
Ответ: 50 км

Answer 2

Problem Analysis

We are given that a train traveled a distance of 210 km. It initially traveled at a speed of 60 km/h and then reduced its speed to 20 km/h due to an accident. The total time taken to cover the entire distance was 6 hours. We need to find the length of the section where the train was traveling at a reduced speed.

Solution

Let's assume that the length of the accident section is x km.

To find the length of the accident section, we can use the formula: distance = speed × time.

The time taken to cover the first part of the journey at a speed of 60 km/h can be calculated as (210 - x) / 60 hours.

The time taken to cover the accident section at a speed of 20 km/h can be calculated as x / 20 hours.

According to the given information, the total time taken to cover the entire distance is 6 hours. Therefore, we can write the equation:

(210 - x) / 60 + x / 20 = 6

To solve this equation, we can multiply through by the least common multiple (LCM) of the denominators, which is 60:

60 * [(210 - x) / 60 + x / 20] = 60 * 6

Simplifying the equation:

(210 - x) * 20 + 3x * 60 = 360

Expanding and simplifying further:

4200 - 20x + 180x = 360

Combining like terms:

160x = 3840

Dividing both sides by 160:

x = 24

Therefore, the length of the accident section is 24 km.

Answer

The length of the accident section of the journey is 24 km.