Question

Из пункта A в пункт B вышел пешеход. Когда он прошёл 1200 м, из пункта А в пункт В выехал велосипедист и через 15 минут догнал пешехода, поскольку его скорость в два раза больше скорости пешехода.Чему равна скорость пешехода?

Answer 1

Х - скорость пешехода
Скорость велосипедиста - 2x
Время пешехода  t = 1200 / x
Время велосипедиста t + 15 = 1200/x +15
Cоставим уравнение:
х * (1200/x + 15)= 2x * 15
15x + 1200 = 30x
15x = 1200
x = 80
Скорость пешехода 80 м/мин.
Найдем время, которое затратил пешеход, чтобы пройти 1200 м.:
1200/ 80= 15 мин.
Найдем общее время пешехода:
15+15 = 30 мин.
Скорость велосипедиста:
2 * 80 = 160 м/мин.
Узнаем расстояние, которое прошел пешеход:
80 * 30 = 2400 м.
Расстояние, которое проехал велосипедист:
160 * 15 = 2400 м.
Ответ: скорость пешехода v = 80 м/мин.

Answer 2

Calculation of the Pedestrian's Speed

To determine the speed of the pedestrian, let's analyze the given information step by step.

1. The pedestrian walks from point A to point B and covers a distance of 1200 meters. 2. After the pedestrian has walked 1200 meters, a cyclist starts from point A and catches up with the pedestrian in 15 minutes. 3. The cyclist's speed is twice that of the pedestrian.

To find the pedestrian's speed, we need to calculate the cyclist's speed first. We can use the formula:

Speed = Distance / Time

Let's calculate the cyclist's speed:

1. The cyclist catches up with the pedestrian in 15 minutes, which is equivalent to 15/60 = 0.25 hours. 2. The distance covered by the cyclist is the same as the distance covered by the pedestrian, which is 1200 meters.

Using the formula, we can calculate the cyclist's speed:

Cyclist's Speed = 1200 meters / 0.25 hours

Now, let's calculate the cyclist's speed using the given information.

Calculation of the Cyclist's Speed

The cyclist's speed can be calculated as follows:

Cyclist's Speed = 1200 meters / 0.25 hours = 4800 meters per hour

Calculation of the Pedestrian's Speed

Since the cyclist's speed is twice that of the pedestrian, we can calculate the pedestrian's speed by dividing the cyclist's speed by 2:

Pedestrian's Speed = Cyclist's Speed / 2 = 4800 meters per hour / 2

Now, let's calculate the pedestrian's speed using the calculated cyclist's speed.

Final Calculation of the Pedestrian's Speed

Pedestrian's Speed = 4800 meters per hour / 2 = 2400 meters per hour

Therefore, the speed of the pedestrian is 2400 meters per hour.

Please note that the given information does not provide the exact time it took for the pedestrian to walk 1200 meters. It only states that the cyclist caught up with the pedestrian after 15 minutes.