Question

Навстречу друг другу едут два поезда.Скорость одного из них равна а км/ч,что составляет 4/5 скорости другой поезда.Чему равна их скорость сближения?

Answer 1

Скорость сближения:a+4/5a

Answer 2

Problem Analysis

We are given that two trains are approaching each other. The speed of one train is "a" km/h, which is 4/5 times the speed of the other train. We need to find the speed at which the trains are approaching each other.

Solution

Let's assume the speed of the slower train is "x" km/h. According to the given information, the speed of the faster train is 4/5 times the speed of the slower train, which can be expressed as (4/5)x km/h.

When two objects are moving towards each other, their relative speed is the sum of their individual speeds. Therefore, the speed at which the two trains are approaching each other is x km/h + (4/5)x km/h.

To find the value of x, we can set up an equation using the given information. The sum of the speeds of the two trains is equal to the distance between them divided by the time taken to cover that distance.

Let's assume the distance between the two trains is "d" km, and the time taken to cover that distance is "t" hours. The equation can be written as:

x km/h + (4/5)x km/h = d km / t hours

Simplifying the equation, we get:

(9/5)x km/h = d km / t hours

To find the speed at which the trains are approaching each other, we need to find the value of x.

Calculation

Unfortunately, the given information does not provide the values of "d" and "t". Without these values, we cannot calculate the exact speed at which the trains are approaching each other.

If you have the values of "d" and "t", you can substitute them into the equation and solve for "x". Then, you can calculate the speed at which the trains are approaching each other by substituting the value of "x" into the expression x km/h + (4/5)x km/h.

Please provide the values of "d" and "t" so that we can calculate the speed at which the trains are approaching each other.

Note: The given information does not provide enough details to calculate the speed at which the trains are approaching each other.