Question

Расстояние между двумя городами 900 км.Два поезда вышли из этих городов навстречу друг другу со скоростями 60 км/ч и 80 км/ч.На каком расстоянии друг от друга были поезда за 1 час до встречи? через 1 час после встречи? Есть ли в задаче лишние условия

Answer 1

60 + 80 = 140 км/ч скорость сближения, то есть за каждый час расстояние между поездами уменьшается на 140 км. Значит, за 1 час до их встречи между поездами будет 140 км. После встречи поезда будут удаляться друг от друг со скоростью 140 км/ч. Через 1 час после встречи расстояние между ними будет так же 140 км. Лишнее условие: расстояние между городами.

Answer 2

Problem Analysis

We are given that two trains are traveling towards each other from two cities that are 900 km apart. The speeds of the trains are 60 km/h and 80 km/h. We need to find the distance between the trains 1 hour before their meeting and 1 hour after their meeting. We also need to determine if there are any extraneous conditions in the problem.

Solution

To find the distance between the trains 1 hour before their meeting, we can calculate the total distance covered by both trains in 1 hour and subtract it from the initial distance between the cities.

Let's calculate the distance covered by each train in 1 hour: - Train 1: 60 km/h * 1 h = 60 km - Train 2: 80 km/h * 1 h = 80 km

The total distance covered by both trains in 1 hour is 60 km + 80 km = 140 km.

Therefore, the distance between the trains 1 hour before their meeting is 900 km - 140 km = 760 km.

To find the distance between the trains 1 hour after their meeting, we can calculate the total distance covered by both trains in 2 hours and subtract it from the initial distance between the cities.

Let's calculate the distance covered by each train in 2 hours: - Train 1: 60 km/h * 2 h = 120 km - Train 2: 80 km/h * 2 h = 160 km

The total distance covered by both trains in 2 hours is 120 km + 160 km = 280 km.

Therefore, the distance between the trains 1 hour after their meeting is 900 km - 280 km = 620 km.

Extraneous Conditions

There don't appear to be any extraneous conditions in the problem. The given information is sufficient to solve the problem.

Summary

- The distance between the trains 1 hour before their meeting is 760 km. - The distance between the trains 1 hour after their meeting is 620 km. - There are no extraneous conditions in the problem.

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