Question

Из двух городов навстречу друг другу одновременно отправились два поезда. Скорость одного 60 км/ч, другой за 1 час проходит на 20 км больше. Через 3ч 30мин поезда встретились. Найди расстояние между городами.

Answer 1

Расстояние = время * скорость
скорость сближения = скорость 1 поезда + скорость 2 поезда
60 + (60 + 20) = 140 км/ч
время = 3,5 ч
140 * 3,5 = 490
ответ: 490км

Answer 2

Problem Analysis

We are given that two trains start simultaneously from two cities towards each other. The speed of one train is 60 km/h, while the other train covers 20 km more in 1 hour. After 3 hours and 30 minutes, the trains meet. We need to find the distance between the two cities.

Solution

Let's assume the distance between the two cities is d km.

The first train's speed is 60 km/h, so in 3 hours and 30 minutes (or 3.5 hours), it covers a distance of 60 * 3.5 = 210 km.

The second train covers 20 km more than the first train in 1 hour. So, in 3 hours and 30 minutes, it covers a distance of (60 + 20) * 3.5 = 280 km.

When the two trains meet, the total distance covered by both trains is equal to the distance between the two cities.

Therefore, we can write the equation:

210 + 280 = d

Simplifying the equation, we find:

d = 490 km

So, the distance between the two cities is 490 km.

Answer

The distance between the two cities is 490 km.