Question

Два поездаидут на встречу друг другу. Скорость одного из них 80 км./ч , а скорость второго в 1 1/7 раза меньше. Через сколько времени они встретятся, если сейчас между ними 70 км?

Answer 1

1.Ск. второго = 80 : (8/7) = 70
2. Ск. сближения = 70 + 80 = 150
3. Путь дели на ск. и получай врем

Answer 2

Problem Analysis

We are given two trains traveling towards each other. The speed of one train is 80 km/h, while the speed of the other train is 1 1/7 times slower. The distance between them is 70 km. We need to determine how long it will take for the trains to meet.

Solution

To solve this problem, we can use the formula: time = distance / relative speed.

Let's calculate the relative speed of the two trains. The speed of the second train is 1 1/7 times slower than the speed of the first train. We can express this as a fraction: 1/7. The relative speed is then the difference between the speeds of the two trains.

The relative speed is given by:

Relative speed = Speed of the first train - Speed of the second train

Let's calculate the relative speed:

Relative speed = 80 km/h - (80 km/h * 1/7) km/h

Simplifying the expression:

Relative speed = 80 km/h - (80/7) km/h

Now, we can calculate the time it will take for the trains to meet:

Time = Distance / Relative speed

Substituting the given distance of 70 km and the calculated relative speed:

Time = 70 km / (80 km/h - (80/7) km/h)

Simplifying the expression:

Time = 70 km / (560/7 - 80/7) km/h

Time = 70 km / (480/7) km/h

Time = (70 * 7) km / 480 km/h

Time = 490 km / 480 km/h

Time = 1.02083 hours

Converting hours to minutes:

Time = 1.02083 hours * 60 minutes/hour

Time ≈ 61.25 minutes

Therefore, the two trains will meet in approximately 61.25 minutes.

Answer

The two trains will meet in approximately 61.25 minutes.