Question

Через 2 ч после выхода со станции А тепловоз увеличил скорость на 12 км/ч и через 5 ч после начала движения прибыл в пункт назначения В. Какова была скорость тепловоза в начале пути если расстояние от А до Б равно 260 кмПжжж

Answer 1

Х скорость в начале пути
х+12 новая скорость
2х+3(х+12)=260
2х+3х+36=260
5х=224
х=44,8км/час первоначальная скорость

Answer 2

Problem Analysis

We are given the following information: - The train departs from station A and arrives at destination B. - The train increases its speed by 12 km/h after 2 hours of departure from station A. - The train arrives at destination B after 5 hours of starting its journey. - The distance between station A and destination B is 260 km.

We need to determine the initial speed of the train.

Solution

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

We can calculate the time taken by the train to travel from station A to destination B using the formula:

Time = Distance / Speed

The time taken for the first part of the journey (2 hours) can be calculated as:

Time1 = 2 hours

The time taken for the second part of the journey (5 hours) can be calculated as:

Time2 = 5 hours

The total time taken for the journey can be calculated as:

Total Time = Time1 + Time2

The distance between station A and destination B is given as 260 km.

Using the formula for time, we can write the following equations:

Time1 = Distance / Initial Speed

Time2 = Distance / (Initial Speed + 12)

Substituting the values, we get:

2 = 260 / Initial Speed

5 = 260 / (Initial Speed + 12)

We can solve these equations to find the initial speed of the train.

Let's solve the equations step by step:

From the first equation, we can find the value of Initial Speed:

Initial Speed = 260 / 2

Initial Speed = 130 km/h

Substituting the value of Initial Speed in the second equation, we can find the value of Initial Speed + 12:

5 = 260 / (130 + 12)

Simplifying the equation:

5 = 260 / 142

5 = 1.83098591549

Therefore, the initial speed of the train was 130 km/h.

Answer

The initial speed of the train was 130 km/h.