Question

Из пунктов А и Б, расстояние между которыми 21 км, отправляются в путь одновременно пешеход из В и вдогонку ему велосипидист из А и движутся со скоростью: пешеход 5 км/ч, велосипедист 12 км/ч. На сколько километров уменьшится расстояние между ними через 3 часа?

Answer 1

5*3=15
12*3=36
15+36=51

Answer 2

Нам нужно найти расстояние, пройденное за 3 часа пешеходом и за 3 часа велосипедистом, потом сложить.
Прошел пешеход: 5*3=15 км.
Проехал велосипедист:12*3=36 км.
Прошли вместе:15+36=51 км.
Ответ: расстояние между ними за 3 часа уменьшится на 51 км.

Answer 3

Problem Analysis

We are given two points, A and B, which are 21 km apart. A pedestrian starts walking from point B towards point A at a speed of 5 km/h, and a cyclist starts chasing the pedestrian from point A towards point B at a speed of 12 km/h. We need to determine the distance between them after 3 hours.

Solution

To solve this problem, we can calculate the distance covered by the pedestrian and the cyclist separately and then find the difference between the two distances.

Let's calculate the distance covered by the pedestrian after 3 hours: Distance = Speed * Time Distance = 5 km/h * 3 h = 15 km

Now, let's calculate the distance covered by the cyclist after 3 hours: Distance = Speed * Time Distance = 12 km/h * 3 h = 36 km

To find the difference between the distances, we subtract the distance covered by the pedestrian from the distance covered by the cyclist: Difference = Distance of Cyclist - Distance of Pedestrian Difference = 36 km - 15 km = 21 km

Therefore, the distance between the pedestrian and the cyclist after 3 hours will be 21 km.

Answer

The distance between the pedestrian and the cyclist after 3 hours will be 21 km.