Question

Из пункта А в пункт Б одновременно отправились пешеход и велосипедист. Велосипедист приехав в пункт Б не меняя скорости повернул обратно и встретился с пешеходом ровно через два часа. С какими скоростями сближались пешеход и велосипедист если расстояние между А и Б 15 км.

Answer 1

2*Х+2*У=15+15=30 ( это путь до совместной встречи 30 км, так как велосипедист проехал весь путь из А в Б и возвращался)

Х+У=15
Х скорость пешехода У скорость велосипедиста
сумма скоростей 15 км/ч    7 и 8; 6 и 9;
5 и10 ; 4 и 11; 3 и 12 и т.д.

Answer 2

Problem Analysis

To solve this problem, we need to find the speeds at which the pedestrian and the cyclist were approaching each other. We know that the distance between points A and B is 15 km, and the cyclist, after reaching point B, turned back without changing his speed and met the pedestrian exactly two hours later.

Solution

Let's denote the speed of the pedestrian as P and the speed of the cyclist as C. Since they were moving towards each other, their combined speed would be the sum of their individual speeds.

Calculating the Distance Covered

- The pedestrian covers a distance of 15 km in the same time it takes for the cyclist to cover the same distance and return to meet the pedestrian. This means the pedestrian covers the distance in 2 hours. - The cyclist covers the same 15 km distance in the time it takes for him to meet the pedestrian after turning back. This time is 2 hours.

Calculating the Speeds

Using the formula: Speed = Distance / Time, we can calculate the speeds of the pedestrian and the cyclist.

- For the pedestrian: P = 15 km / 2 hours = 7.5 km/h. - For the cyclist: C = 15 km / 2 hours = 7.5 km/h.

Conclusion

Therefore, the pedestrian and the cyclist were approaching each other at speeds of 7.5 km/h each.

This solution assumes constant speeds for both the pedestrian and the cyclist.