Question

Из двух пунктов расстояние между которыми 40 км навстречу друг другу одновременно отправились пешеход и велосипедист скорость велосипеда в 4 раза больше скорости пешехода найдите скорости пешехода и велосипедиста если известно что они встретились через 2,5ч после своего выхода

Answer 1

Пусть х км/ч - скорость пешехода, тогда скорость велосипедиста 4х км/ч.
s = v * t - формула пути
v = х + 4х = 5х (км/ч) - скорость сближения
t = 2,5 (ч) - время в пути
s = 40 (км) - расстояние между двумя пунктами
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5х * 2,5 = 40
5х = 40 : 2,5
5х = 16
х = 16 : 5
х = 3,2 (км/ч) - скорость пешехода
4 * 3,2 = 12,8 (км/ч) - скорость велосипедиста
Ответ: 3,2 км/ч и 12,8 км/ч. 

Answer 2

Problem Analysis

We are given that the distance between two points is 40 km. A pedestrian and a cyclist start simultaneously from these two points towards each other. The speed of the cyclist is 4 times greater than the speed of the pedestrian. We need to find the speeds of the pedestrian and the cyclist if they meet after 2.5 hours.

Solution

Let's assume the speed of the pedestrian is x km/h. Since the speed of the cyclist is 4 times greater, the speed of the cyclist is 4x km/h.

We know that distance = speed × time. The pedestrian and the cyclist meet after 2.5 hours, so the total distance covered by both of them is 40 km.

The distance covered by the pedestrian is x × 2.5 km, and the distance covered by the cyclist is 4x × 2.5 km.

According to the problem, the sum of these distances is equal to 40 km:

x × 2.5 + 4x × 2.5 = 40

Simplifying the equation:

2.5x + 10x = 40

12.5x = 40

x = 40 / 12.5

x = 3.2

So, the speed of the pedestrian is 3.2 km/h and the speed of the cyclist is 4 × 3.2 = 12.8 km/h.

Therefore, the speed of the pedestrian is 3.2 km/h and the speed of the cyclist is 12.8 km/h.