Question

Первый велосипедист выехал из поселка по шоссе со скоростью 12 км/ч. Через час после него со скоростью 10 км/ч из того же поселка в том же направлении выехал второй велосипедист, а еще через час после этого — третий. Найдите скорость третьего велосипедиста, если сначала он догнал второго, а через 2 часа 45 минут после этого догнал первого. Ответ дайте в км/ч. . Желательно расписать все по понятиям. Не принимается похожие задачи, с другими цифрами.

Answer 1

Ответ находится тут . Там 2 ответа
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Answer 2

Problem Analysis

We are given the following information: - The first cyclist travels at a speed of 12 km/h. - One hour later, the second cyclist starts from the same village and travels at a speed of 10 km/h. - One hour after the second cyclist starts, the third cyclist starts and eventually catches up to the second cyclist. - Two hours and 45 minutes after the third cyclist starts, they catch up to the first cyclist.

We need to find the speed of the third cyclist.

Solution

Let's break down the problem step by step:

1. Let's assume the distance between the village and the point where the third cyclist catches up to the second cyclist is D kilometers. 2. The first cyclist has been cycling for 2 hours and 45 minutes when the third cyclist catches up to them. This means the first cyclist has traveled a distance of 12 km/h * (2.75 hours). 3. The second cyclist has been cycling for 1 hour when the third cyclist catches up to them. This means the second cyclist has traveled a distance of 10 km/h * 1 hour. 4. Since the third cyclist catches up to the second cyclist, the distance traveled by the third cyclist is equal to the difference in distances traveled by the first and second cyclists: 12 km/h * (2.75 hours) - 10 km/h * 1 hour. 5. Therefore, the speed of the third cyclist can be calculated by dividing the distance traveled by the third cyclist by the time it took them to catch up to the second cyclist: (12 km/h * (2.75 hours) - 10 km/h * 1 hour) / (2.75 hours - 1 hour).

Let's calculate the speed of the third cyclist:

Distance traveled by the third cyclist = 12 km/h * (2.75 hours) - 10 km/h * 1 hour = 33 km - 10 km = 23 km

Time taken by the third cyclist to catch up to the second cyclist = 2.75 hours - 1 hour = 1.75 hours

Speed of the third cyclist = (23 km) / (1.75 hours) = 13.14 km/h

Therefore, the speed of the third cyclist is approximately 13.14 km/h.

Answer

The speed of the third cyclist is approximately 13.14 km/h.