Question

Два поезда вышли одновременно навстречу друг другу из двух городов,расстояние между которыми 490 км.Один поезд проходит в 1/5 часа 10 км,а другой в 1/8 часа 6 км.Чрез сколько часов поезда встретятся?

Answer 1

1)10*5=50(км)-за час
2)6*8=48(км)за час
490/(48+50)=5(ч)
ответ:5 часов

Answer 2

Problem Analysis

We have two trains traveling towards each other from two different cities. The distance between the cities is 490 km. The first train travels at a speed of 10 km in 1/5 hour, while the second train travels at a speed of 6 km in 1/8 hour. We need to find out how many hours it will take for the trains to meet.

Solution

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. Let's calculate the relative speed and then use it to find the time.

Calculation

The first train travels at a speed of 10 km in 1/5 hour, so its speed is:

Speed of first train = 10 km / (1/5) hour = 50 km/hour

Similarly, the second train travels at a speed of 6 km in 1/8 hour, so its speed is:

Speed of second train = 6 km / (1/8) hour = 48 km/hour

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

Relative speed = Speed of first train + Speed of second train = 50 km/hour + 48 km/hour = 98 km/hour

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

Time = Distance / Relative Speed = 490 km / 98 km/hour = 5 hours

Therefore, the trains will meet after 5 hours.

Answer

The two trains will meet after 5 hours.