Question

2. Расстояние между двумя городами 1371 км. Из них вышли навстречу два поезда. Первый вышел в 3 ч утра и проходил по 48км/ч. Второй, вышел спустя 5 ч и делал 39 км/ч. В котором часу поезда встретятся?

Answer 1

Ответ:

1) 48х+39(х-5)=1371

2) 48х+39х-195=1371

3) 87х=1566

4)х=18 час-прошло от начала пути

5) 3+18=21 (ч)

Ответ:В 21 час поезда встретились

Answer 2

Problem Analysis

We are given the distance between two cities (1371 km) and the speeds of two trains. We need to determine at what time the trains will meet.

Solution

To solve this problem, we can use the formula: time = distance / speed. We'll calculate the time it takes for each train to cover the given distance and then determine at what time they will meet.

Let's calculate the time it takes for the first train to cover the distance: - Distance: 1371 km - Speed: 48 km/h - Time = Distance / Speed = 1371 km / 48 km/h = 28.5625 hours

Now, let's calculate the time it takes for the second train to cover the distance: - Distance: 1371 km - Speed: 39 km/h - Time = Distance / Speed = 1371 km / 39 km/h = 35.1538 hours

Since the second train departs 5 hours after the first train, we need to add 5 hours to the time it takes for the second train to cover the distance: - Total time for the second train = 35.1538 hours + 5 hours = 40.1538 hours

To find the time at which the trains will meet, we need to add the time it takes for the first train to cover the distance to the time it takes for the second train to cover the distance: - Total time = 28.5625 hours + 40.1538 hours = 68.7163 hours

Now, we need to convert the total time to hours and minutes. Since there are 60 minutes in an hour, we can multiply the decimal part of the total time by 60 to get the minutes: - Decimal part of total time = 0.7163 - Minutes = 0.7163 * 60 = 42.978 minutes

Therefore, the trains will meet approximately 68 hours and 43 minutes after the first train departs.

Answer

The trains will meet approximately 68 hours and 43 minutes after the first train departs.