Question

Пешеход вышел из пункта А, одновременно с ним из пункта В выехал велосипедист. Через 15 мин они встретились, а ещё через 9 мин велосипедист приехал в пункт А. За сколько минут пешеход проходит расстояние от А до В?

Answer 1

15+9=24(мин)идти пешеходу от пункта А до В

Answer 2

Problem Analysis

We are given that a pedestrian leaves point A at the same time a cyclist leaves point B. After 15 minutes, they meet, and after an additional 9 minutes, the cyclist arrives at point A. We need to determine how long it takes for the pedestrian to travel from point A to point B.

Solution

Let's assume that the pedestrian's speed is x units per minute and the cyclist's speed is y units per minute. We can set up two equations based on the information given:

Equation 1: The distance traveled by the pedestrian in 15 minutes is equal to the distance traveled by the cyclist in 15 minutes plus the distance traveled by the cyclist in the additional 9 minutes. Equation 2: The distance traveled by the cyclist in 9 minutes is equal to the distance between point A and point B.

Using these equations, we can solve for the unknowns.

Calculation

Let's denote the distance between point A and point B as d.

Equation 1: 15x = 15y + 9y Equation 2: 9y = d

From Equation 2, we can express y in terms of d: y = d/9.

Substituting this value of y into Equation 1, we get: 15x = 15(d/9) + 9(d/9).

Simplifying the equation, we have: 15x = (15d + 9d)/9.

Multiplying both sides of the equation by 9, we get: 135x = 24d.

Dividing both sides of the equation by 24, we have: x = d/5.625.

Therefore, the pedestrian's speed is d/5.625 units per minute.

To find the time it takes for the pedestrian to travel from point A to point B, we can use the formula time = distance/speed. In this case, the distance is d and the speed is d/5.625.

Therefore, the time it takes for the pedestrian to travel from point A to point B is d/(d/5.625) = 5.625 minutes.

Answer

The pedestrian takes 5.625 minutes to travel from point A to point B.