Question

От автобусной станции отошел автобус со скоростью 40 км/ч. Через час в противоположном направлении вышел другой автобус, скорость которого 60км/ч. Через какое время после выхода второго автобуса расстояние между ними будет равно 140 км? Через какое время после выхода первого автобуса расстояние между ними будет равно 240 км?

Answer 1

1)   40*1=40(км)-проехал первый до выезда второго
2)   40+60=100(км/ч)-скорость расхождения
3)   (140-40):100=1(ч)-через столько между ними будет 140 км
4)   (240+40):100=2,8(ч)-потребуется времени

Answer 2

Problem Analysis

We are given two buses that start from the same point but travel in opposite directions. The first bus has a speed of 40 km/h, and the second bus has a speed of 60 km/h. We need to find the time it takes for the distance between the two buses to be equal to 140 km and 240 km, respectively.

Solution

Let's first calculate the time it takes for the distance between the two buses to be 140 km.

Let's assume that the time taken by the second bus to cover the distance of 140 km is 't' hours. Since the second bus is traveling in the opposite direction, its effective speed is the sum of its actual speed and the speed of the first bus, which is 60 km/h + 40 km/h = 100 km/h.

Using the formula: distance = speed × time, we can write the equation as follows: 140 km = 100 km/h × t

Simplifying the equation, we get: t = 140 km / 100 km/h t = 1.4 hours

Therefore, it will take 1.4 hours for the distance between the two buses to be equal to 140 km.

Now, let's calculate the time it takes for the distance between the two buses to be 240 km.

Let's assume that the time taken by the first bus to cover the distance of 240 km is 't' hours. Since the first bus is traveling in the opposite direction, its effective speed is the sum of its actual speed and the speed of the second bus, which is 40 km/h + 60 km/h = 100 km/h.

Using the formula: distance = speed × time, we can write the equation as follows: 240 km = 100 km/h × t

Simplifying the equation, we get: t = 240 km / 100 km/h t = 2.4 hours

Therefore, it will take 2.4 hours for the distance between the two buses to be equal to 240 km.

Answer

After the second bus starts, it will take approximately 1.4 hours for the distance between the two buses to be equal to 140 km. After the first bus starts, it will take approximately 2.4 hours for the distance between the two buses to be equal to 240 km.