Question

Два велосип. ехали из одного города в другой . Первый ехал со скоростью 12 км \ ч а второй 9км\ч . Конда первый отъехал от города 36 км , а второй 54 км , они оба расположились на отдых , после чего они в одно и тоже время начали продолжать свой путь. Через какое время после отдыха велосипедисты будут на одинаковом расстоянии от города?

Answer 1

Пока первый отдыхал второй уехал от него на
54-36=18 км
когда они повторно начали движение первый догоняет второго со скоростью
12-9=3 км/ч
значит он догонит его через
18:3=6 часов. и они будут на растоянии
12*6+36=108 км
9*6+54=108 км от города

Answer 2

Problem Analysis

We have two cyclists traveling from one city to another. The first cyclist is traveling at a speed of 12 km/h, while the second cyclist is traveling at a speed of 9 km/h. After the first cyclist has traveled 36 km from the city and the second cyclist has traveled 54 km from the city, they both take a rest. We need to determine how much time it will take for the cyclists to be at the same distance from the city after their rest.

Solution

To solve this problem, we can use the concept of relative speed. The relative speed between the two cyclists is the difference in their speeds. In this case, the relative speed is 12 km/h - 9 km/h = 3 km/h.

Let's assume that it takes t hours for the cyclists to be at the same distance from the city after their rest. During this time, the first cyclist will travel a distance of 12t km, and the second cyclist will travel a distance of 9t km.

According to the problem, the first cyclist has already traveled 36 km from the city, so the total distance traveled by the first cyclist is 36 + 12t km. Similarly, the second cyclist has already traveled 54 km from the city, so the total distance traveled by the second cyclist is 54 + 9t km.

Since both cyclists are at the same distance from the city after their rest, we can set up the following equation:

36 + 12t = 54 + 9t

Simplifying the equation, we get:

3t = 18

Dividing both sides by 3, we find:

t = 6

Therefore, it will take 6 hours for the cyclists to be at the same distance from the city after their rest.

Answer

After their rest, the cyclists will be at the same distance from the city after 6 hours.