Question

Из пункта А в пункт В вышел пешеход со скоростью 4,8 км/час, а из пункта В в пункт А вышел второй пешеход со скоростью 5,5 км/ч. На расстоянии 12 км от пункта А пешеходы встретились. На сколько часов раньше вышел первый пешеход, если расстояние между пунктами равно 19,7 км?

Answer 1

12^4.8=2.5 часа шел первый до встречи
19.7-12=7.7км прошел второй до встречи
7.7^5.5=1.4 часа шел второй до встречи
2.5-1.4=1.1часа выше первый раньше

Answer 2

Problem Analysis

We are given that two pedestrians start walking from point A to point B and from point B to point A, respectively. The first pedestrian walks at a speed of 4.8 km/h, while the second pedestrian walks at a speed of 5.5 km/h. The distance between point A and point B is 19.7 km. The pedestrians meet each other at a point that is 12 km away from point A. We need to determine how many hours earlier the first pedestrian started walking.

Solution

Let's assume that the first pedestrian started walking x hours earlier than the second pedestrian. We can use the formula `distance = speed * time` to calculate the time taken by each pedestrian to reach the meeting point.

For the first pedestrian: - Speed = 4.8 km/h - Time = x hours - Distance = 12 km

For the second pedestrian: - Speed = 5.5 km/h - Time = (x - t) hours (where t is the time taken by the first pedestrian to reach the meeting point) - Distance = 19.7 km - 12 km = 7.7 km

Using the formula `distance = speed * time`, we can set up the following equations:

Equation 1: 4.8 * x = 12 Equation 2: 5.5 * (x - t) = 7.7

We can solve these equations simultaneously to find the values of x and t.

Detailed Solution

Let's solve the equations step by step.

From Equation 1, we have: 4.8 * x = 12

Simplifying the equation, we get: x = 12 / 4.8 x = 2.5 hours

Now, let's substitute the value of x into Equation 2: 5.5 * (2.5 - t) = 7.7

Expanding the equation, we get: 13.75 - 5.5t = 7.7

Rearranging the equation, we get: 5.5t = 13.75 - 7.7 5.5t = 6.05

Dividing both sides by 5.5, we get: t = 6.05 / 5.5 t ≈ 1.1 hours

Therefore, the first pedestrian started walking approximately 2.5 hours earlier than the second pedestrian, and the second pedestrian took approximately 1.1 hours to reach the meeting point.

Answer

The first pedestrian started walking approximately 2.5 hours earlier than the second pedestrian.