Question

Скорый поезд проезжает расстояние между двумя городами, равное 900 км, за 10 ч, а товарный- за 15 ч. Через сколько часов два этих поезда встретятся, если одновременно выйдут из двух городов навстречу друг другу?

Answer 1

900:10=90 км/час скорость скорого поезда                                                                    900:15=60 км/час скорость товарного поезда                                                              90+60=150 км  скорость сближения поездов                                                                                                               900:150=6 часов                                                                                                             ответ- через 6 часов встретятся

Answer 2

900:10=90км/ч скорость скор.п

900:15=60км/ч скор. груз.п

60+90=150 км/ч скорость сближения

900:150=6 часов

Ответ: встретятся через 6 часов

Answer 3

Problem Analysis

We are given that a fast train travels a distance of 900 km in 10 hours, while a freight train travels the same distance in 15 hours. We need to determine how many hours it will take for these two trains to meet if they start simultaneously from two different cities and travel towards each other.

Solution

To solve this problem, we can use the concept of relative speed. The relative speed between the two trains is the sum of their individual speeds when they are moving towards each other.

Let's assume the speed of the fast train is v1 and the speed of the freight train is v2.

We know that the distance traveled by the fast train in 10 hours is 900 km, so we can calculate its speed as:

v1 = distance / time = 900 km / 10 hours = 90 km/h.

Similarly, the speed of the freight train can be calculated as:

v2 = distance / time = 900 km / 15 hours = 60 km/h.

Now, to find the time it takes for the two 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:

relative speed = v1 + v2 = 90 km/h + 60 km/h = 150 km/h.

Substituting the values into the formula, we get:

time = 900 km / 150 km/h = 6 hours.

Therefore, the two trains will meet after 6 hours.

Answer

The fast train and the freight train will meet after 6 hours if they start simultaneously from two different cities and travel towards each other.