Question

Из пункта А в пункт В,расположенный на расстоянии 120 км,отправился атобус со скоростью 45 км/ч. Как только автобус проехал треть пути, вслед за ним выехала машина. В пункт В они прибыли одновременно. Найдите скорость машины (в км/ч).

Answer 1

Автобус и машина за одно и то же время проехали разное расстояние. 

Автобус 2/3 от 120 км,  машина - все 120 км

 Примем скорость машины за х

Автобус проехал 80 км за то же время, за которое машина проехала 120 км

время автобуса 80:45

время машины 120:х

приравняем их

80:45=120:х

45*120=80х

80х=5400

х=67,5 км/чскорость машины

Answer 2

Problem Analysis

We are given that a bus travels from point A to point B, which are 120 km apart, at a speed of 45 km/h. After the bus has traveled one-third of the distance, a car starts from point A and reaches point B at the same time as the bus. We need to find the speed of the car in km/h.

Solution

Let's assume the speed of the car is x km/h.

We know that the distance traveled by the bus is one-third of the total distance, which is 120 km. Therefore, the distance traveled by the bus is (1/3) * 120 = 40 km.

We can calculate the time taken by the bus to travel this distance using the formula: time = distance / speed. Substituting the values, we get:

time taken by the bus = 40 km / 45 km/h = 4/9 hours

Since the car and the bus reach point B at the same time, the time taken by the car to travel the entire distance of 120 km is also 4/9 hours.

We can now calculate the speed of the car using the formula: speed = distance / time. Substituting the values, we get:

speed of the car = 120 km / (4/9) hours = (120 * 9) / 4 km/h = 270 / 4 km/h = 67.5 km/h

Therefore, the speed of the car is 67.5 km/h.

Answer

The speed of the car is 67.5 km/h.