Question

Из двух городов, расстояние между которыми 45 км, одновременно в одном направлении вышли поезда со скоростью 70 км/ч и 60 км/ч, причём первый поезд догоняет второй. Через сколько часов расстояние между поездами будет равно 10 км?

Answer 1

1) 70 - 60 = 10 (км/ч) - разница в скоростях
2) 45 - 10 = 35 (км) - необходимо сократить расстояние
3) 35 : 10 = 3,5 (ч) 
Ответ : 3,5 часа необходимо для сокращения расстояния до 10 км.

Answer 2

1) 70-60=10 км\ч - их общая скорость сближения2) 45-10=35 км - нужно им проехать до отметки 10 км3) 35:10=3,5 часа - потребуется

Answer 3

Problem Analysis

We are given two cities that are 45 km apart. Two trains start simultaneously from these cities in the same direction. The first train has a speed of 70 km/h, and the second train has a speed of 60 km/h. We need to find out how many hours it will take for the first train to catch up to the second train when the distance between them is 10 km.

Solution

Let's assume that it takes "t" hours for the first train to catch up to the second train. During this time, the first train will travel a distance of 70t km, and the second train will travel a distance of 60t km.

According to the problem, the distance between the trains will be 10 km when the first train catches up to the second train. Therefore, we can set up the following equation:

70t - 60t = 10

Simplifying the equation, we get:

10t = 10

Dividing both sides of the equation by 10, we find:

t = 1

Therefore, it will take 1 hour for the first train to catch up to the second train when the distance between them is 10 km.

Answer

The first train will catch up to the second train when the distance between them is 10 km after 1 hour.