Question

Два поезда отправились одновременно навстречу друг другу из двух городов.Скорость первого поезда 85км/ч а скорость второго 60км/ч.Через 3 часа после отправления расстояние между поездами было равно 290км.Найди расстояние между этими городами.Через сколько часов после отправления поезда в стретятся

Answer 1

Поезда сближались со скоростью 65+80=145 км/ч
За 3 часа они проехали 145*3=435 км
Значит между городами 435+290=725км
Встретятся они через 725:145=5 часов.

Answer 2

1) 85 * 3 = 255 км проехал первый
2) 60 * 3 = 180 км проехал второй
3) 255 + 180 + 290 = 725 км расстояние между городами
4) 85 + 60 = 145 км/ч скорость сближения
5) 725 : 145 = 5 ч через 5 часов встретятся

Answer 3

Problem Analysis

We are given two trains that start simultaneously from two different cities and are moving towards each other. The speed of the first train is 85 km/h, and the speed of the second train is 60 km/h. After 3 hours, the distance between the trains is 290 km. We need to find the distance between the two cities and the time it takes for the trains to meet.

Distance between the Cities

To find the distance between the two cities, we can use the formula:

Distance = Speed × Time

Let's denote the distance between the two cities as 'D'. The first train travels for 3 hours at a speed of 85 km/h, so the distance it covers is 85 km/h × 3 h = 255 km. The second train also travels for 3 hours at a speed of 60 km/h, so the distance it covers is 60 km/h × 3 h = 180 km.

Since the two trains are moving towards each other, the sum of the distances covered by both trains will be equal to the total distance between the two cities:

255 km + 180 km = D

Therefore, the distance between the two cities is 435 km.

Time to Meet

To find the time it takes for the trains to meet, we can use the formula:

Time = Distance / Relative Speed

The relative speed of the two trains is the sum of their individual speeds:

Relative Speed = Speed of First Train + Speed of Second Train

Substituting the given values:

Relative Speed = 85 km/h + 60 km/h = 145 km/h

Now we can calculate the time it takes for the trains to meet:

Time = Distance / Relative Speed = 435 km / 145 km/h = 3 hours

Therefore, the trains will meet 3 hours after their departure.

Summary

The distance between the two cities is 435 km. The trains will meet 3 hours after their departure.

Please let me know if I can help you with anything else.