Question

Три друга добирались из пункта А в пункт Б, а затем в пункт В. Начали и закончили движение они одновременно. Вася из А в Б ехал со скоростью 60 км/ч, а из Б в В со скоростью 12 км/ч. Петя из А в Б ехал со скоростью 72 км/ч, а из Б в В со скоростью 8 км/ч. Коля из А в Б ехал со скоростью 54 км/ч. С какой скоростью (в км/ч) ехал Коля из пункта Б в пункт В?

Answer 1

Ответ:18

Пошаговое объяснение:

пусть отАдоБ обозначим Х, отБ доВ

обозначим -У. Время в пути одинаковое .

х/60+у/12=х/72 +у/8

х=15у от АдоБ 15у ,находим время

в пути, для Васи 15у/60+у/12=у/3

неизвестную скорость для Коли обозначим v, тогда 15у/54+у/v=y/3

откуда v=18

Answer 2

Problem Analysis

Three friends are traveling from point A to point B and then to point C. They start and finish their journey simultaneously. Vasya travels from A to B at a speed of 60 km/h and from B to C at a speed of 12 km/h. Petya travels from A to B at a speed of 72 km/h and from B to C at a speed of 8 km/h. Kolya travels from A to B at a speed of 54 km/h. We need to determine Kolya's speed from point B to point C.

Solution

To find Kolya's speed from point B to point C, we can use the concept of relative speed. The relative speed between two objects traveling in the same direction is the difference between their individual speeds.

Let's calculate Kolya's speed from point B to point C using the relative speed formula:

Relative Speed = Kolya's Speed - Vasya's Speed

Kolya's speed from A to B is given as 54 km/h, and Vasya's speed from A to B is given as 60 km/h. Therefore, the relative speed between Kolya and Vasya from point B to point C is:

Relative Speed = 54 km/h - 60 km/h = -6 km/h

Since the relative speed is negative, it means that Kolya is traveling slower than Vasya from point B to point C. To find Kolya's actual speed, we need to subtract the relative speed from Vasya's speed from B to C.

Kolya's Speed from B to C = Vasya's Speed from B to C - Relative Speed

Vasya's speed from B to C is given as 12 km/h. Substituting the values, we get:

Kolya's Speed from B to C = 12 km/h - (-6 km/h) = 12 km/h + 6 km/h = 18 km/h

Therefore, Kolya's speed from point B to point C is 18 km/h.

Answer

Kolya traveled from point B to point C with a speed of 18 km/h.