Question

Из Москвы в Пермь вышел товарный поезд, который за 3 часа проходит 240 км. Через 5 целых одну вторую часа вслед за ним отправился скорый поезд и через 5 целых одну вторую часа после своего отправления догнал товарный поезд. С какой скоростью шёл скорый поезд?

Answer 1

Товарный поезд пробыл в пути до встречи со скорым 5,5+5,5=11 часов. Его скорость равна 240 км : 3 часа=80км/ч. За 11 часов товарный поезд прошел 80*11=880 км. Столько же километров прошел скорый поезд, но ему потребовалось лишь 5,5 часа.

880 км : 5,5 часа= 160 км/ч - скорость скорого поезда.

 

Ответ: 160 км/ч  - скорость скорого поезда.

Answer 2

Problem Analysis

We are given that a freight train from Moscow to Perm travels 240 km in 3 hours. After 5 hours and 1/2 hour, a fast train departs and catches up to the freight train after 5 hours and 1/2 hour. We need to find the speed of the fast train.

Solution

Let's assume the speed of the freight train is v km/h and the speed of the fast train is x km/h.

We know that the freight train travels 240 km in 3 hours, so we can write the equation:

240 = 3v After 5 hours and 1/2 hour, the fast train departs and catches up to the freight train after 5 hours and 1/2 hour. This means that the fast train traveled for a total of 5 hours and 1/2 hour + 5 hours and 1/2 hour = 11 hours.

During this time, the freight train also traveled for 11 hours. Since the distance traveled by both trains is the same when the fast train catches up to the freight train, we can write the equation:

11x = 240 Now we can solve these two equations simultaneously to find the value of x, which represents the speed of the fast train.

From equation we can solve for v:

v = 240 / 3 = 80 km/h

Substituting this value of v into equation we can solve for x:

11x = 240

x = 240 / 11 ≈ 21.82 km/h

Therefore, the speed of the fast train is approximately 21.82 km/h.

Answer

The fast train was traveling at a speed of approximately 21.82 km/h.