Question

два поезда двигались навстречу друг другу. через 0,5 ч после встречи расстояние между ними стало равным 60 км. найдите скорости поездов, если одна из них на 20 км/ч больше другой

Answer 1

Problem Analysis

We have two trains moving towards each other. After 0.5 hours, the distance between them becomes 60 km. We need to find the speeds of the trains, given that one train is 20 km/h faster than the other.

Solution

Let's assume the speed of the slower train is x km/h. Then the speed of the faster train would be (x + 20) km/h.

We can use the formula distance = speed × time to solve this problem.

The distance covered by the slower train in 0.5 hours is 0.5x km. The distance covered by the faster train in 0.5 hours is 0.5(x + 20) km.

According to the problem, the sum of these distances is equal to 60 km: 0.5x + 0.5(x + 20) = 60

Let's solve this equation to find the value of x.

Calculation

0.5x + 0.5(x + 20) = 60

Simplifying the equation: 0.5x + 0.5x + 10 = 60 1x + 10 = 60 1x = 60 - 10 1x = 50 x = 50

The speed of the slower train is 50 km/h. The speed of the faster train is (50 + 20) = 70 km/h.

Answer

The speed of the slower train is 50 km/h, and the speed of the faster train is 70 km/h.