Question

В разное время из двух городов, расстояние между которыми 940 км, навстречу друг другувышли два поезда.Скорость одного поезда 52км/ч, а скорость второго поезда на 8 км/ч больше.Поезда встретелись через 7 ч после выхода второго поезда.Сколько в пути находился первый поезд?

Answer 1

52+8=60км/ч- скорость второго поезда

60/7=420км- прошел второй поезд до встречи с первым

940-420=520км- прошел первый поезд до встречи со вторым поездом

520/52=10ч- находился в пути первый поезд

 

 

 

 

 

 

Answer 2

Problem Analysis

We are given that two trains start from two different cities, with a distance of 940 km between them. 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. The trains meet after 7 hours from the departure of the second train. We need to find the time the first train was in transit.

Solution

Let's assume the time the first train was in transit is t hours. Since the second train departs 7 hours after the first train, the time the second train was in transit is t - 7 hours.

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

The distance traveled by the first train is given by distance1 = speed1 × t.

The distance traveled by the second train is given by distance2 = speed2 × (t - 7).

Since the trains meet, the sum of their distances should be equal to the total distance between the cities:

distance1 + distance2 = 940 km

Substituting the expressions for distance1 and distance2:

speed1 × t + speed2 × (t - 7) = 940 km

Now we can substitute the given values for speed1 and speed2:

52 km/h × t + (52 km/h + 8 km/h) × (t - 7) = 940 km

Simplifying the equation:

52t + 60(t - 7) = 940

Solving for t:

52t + 60t - 420 = 940

112t = 1360

t = 12.14 hours

Therefore, the first train was in transit for approximately 12.14 hours.

Answer

The first train was in transit for approximately 12.14 hours.