Question

Пассажирский поезд проходит расстояние между двумя городами за 36 ч. Если одновременно из этих городов выйдут навстречу друг другу пассажирский и товарный поезда, то они встретятся через 20 ч после начала движения. За какое время товарный поезд может преодолеть расстояние между городами?

Answer 1

Пассажирский  1отрезок  -36ч
                                х  -  20ч
х=20*1/36
х=0,56
0,56 проехал за 20 ч
товарный проехал 1-0,56=044 
0,44-20ч
1    -х ч
х=1*20/0,44
х=45,5 ч

товарный проедет за 45,5ч

Answer 2

Problem Analysis

We are given that a passenger train travels a certain distance between two cities in 36 hours. If a passenger train and a freight train start from these cities towards each other at the same time, they meet after 20 hours of travel. We need to determine the time it takes for the freight train to cover the distance between the cities.

Solution

Let's assume the distance between the two cities is D.

We know that the passenger train takes 36 hours to cover the distance D. Therefore, the speed of the passenger train can be calculated as:

Speed of passenger train = D / 36 We also know that when the passenger train and the freight train start from their respective cities towards each other, they meet after 20 hours. This means that the combined distance covered by both trains is equal to D.

Let's assume the speed of the freight train is x. Therefore, the distance covered by the freight train in 20 hours is 20x.

Since the combined distance covered by both trains is D, we can write the equation:

D = D/36 * 20 + 20x

Simplifying the equation, we get:

D = (20/36)D + 20x

Multiplying both sides of the equation by 36 to eliminate the fraction, we get:

36D = 20D + 720x

Simplifying further, we get:

16D = 720x

Finally, we can solve for x (the speed of the freight train) by dividing both sides of the equation by 720:

x = 16D / 720

Therefore, the time it takes for the freight train to cover the distance between the cities is:

Time = Distance / Speed = D / (16D / 720) = 720 / 16 = 45 hours

So, the freight train can cover the distance between the cities in 45 hours.

Answer

The freight train can cover the distance between the two cities in 45 hours.

Explanation

Given that the passenger train takes 36 hours to cover the distance between the cities, we can calculate the speed of the passenger train using the formula Speed = Distance / Time. The combined distance covered by both trains is equal to the distance between the cities, and we know that they meet after 20 hours. By setting up an equation using the distances and speeds of both trains, we can solve for the speed of the freight train. Dividing the distance between the cities by the speed of the freight train gives us the time it takes for the freight train to cover the distance. In this case, the freight train can cover the distance in 45 hours.