Question

Два поезда вышли навстречу друг другу в разное время и встретились через 7 часов после выхода второго поезда. скорость первого поезда 52 км/ч , а второго на 8 км/ч больше скорости первого. Сколько часов был в пути первый поезд, если расстояние между городами 940 км?

Answer 1

1)52+8=60 км/ч - скорость 2 поезда

2)60 * 7=420км проехал 2 поезд до встречи

3)940-420=520км проехал 1 поезд до встречи

4)520:52=10часов был в пути 1 поезд

Ответ:10 часов был в пути 1 поезд.

Answer 2

Problem Analysis

We are given that two trains start from different cities and meet each other after 7 hours. The first train has a speed of 52 km/h, while the second train has a speed 8 km/h faster than the first train. We need to find the time it took for the first train to travel a distance of 940 km.

Solution

Let's assume that the time taken by the first train to travel the distance is t hours. Since the second train started later, it traveled for t - 7 hours.

We can use the formula distance = speed × time to calculate the distances traveled by both trains.

For the first train: distance = speed × time = 52t

For the second train: distance = speed × time = (52 + 8)(t - 7) = 60(t - 7)

Since the total distance traveled by both trains is 940 km, we can write the equation: 52t + 60(t - 7) = 940

Now we can solve this equation to find the value of t.

Calculation

Let's solve the equation:

52t + 60(t - 7) = 940

Simplifying the equation:

52t + 60t - 420 = 940

112t - 420 = 940

112t = 1360

t = 1360 / 112

t ≈ 12.14

Answer

The first train was in motion for approximately 12.14 hours to cover a distance of 940 km.