Question

Реши задачу.Вычисли и запиши ответ.Два поезда одновременно отправились от одной станции в противоположных направлениях. Через 2 часа расстояние между ними стало 280 километров.С какой средней скоростью двигался каждый поезд,если у первого поезда она была на 20 км\ч больше,чем у второго?

Answer 1

280:2=140 км в час скорость отдаления
(140-20):2=60 км в час скорость второго
60+20=80 км в час скорость первого

Answer 2

Problem Analysis

We are given that two trains start from the same station in opposite directions. After 2 hours, the distance between them is 280 kilometers. We need to find the average speed of each train, given that the speed of the first train is 20 km/h greater than the speed of the second train.

Solution

Let's assume the speed of the second train is x km/h. Then, the speed of the first train will be x + 20 km/h.

To find the average speed of each train, we can use the formula:

Average Speed = Total Distance / Total Time

The total distance covered by each train after 2 hours is:

- For the first train: (x + 20) km/h * 2 hours - For the second train: x km/h * 2 hours

According to the problem, the distance between the two trains after 2 hours is 280 kilometers. Therefore, we can set up the following equation:

(x + 20) km/h * 2 hours + x km/h * 2 hours = 280 kilometers

Simplifying the equation:

2x + 40 + 2x = 280

4x + 40 = 280

4x = 240

x = 60

Therefore, the speed of the second train is 60 km/h, and the speed of the first train is 60 + 20 = 80 km/h.

Answer

The average speed of the first train is 80 km/h, and the average speed of the second train is 60 km/h.

Explanation

The problem states that the distance between the two trains after 2 hours is 280 kilometers. By setting up and solving the equation, we find that the speed of the second train is 60 km/h and the speed of the first train is 80 km/h.