Question

Товарный поезд должен пройти с постоянной скоростью расстояние между станциями, равная 420 км когда он прошел половину этого расстояния, то был задержан у светофора на 30 минут, поэтому, чтобы наверстать опоздание, машинист увеличилСкорость поезда на 10 км час. С какой скоростью поезд шел до остановки?

Answer 1

Х -первоначальная скорость, х+10 - скорость после остановки, 210 км - путь до остановки, 210/х - время до остановки, 30 мин=0,5 ч - время остановки, 210/(х+10) - время после остановки. Время до и после остановки (+ время остановки) одинаковое, поэтому
210/х=210(х+10)+0,5 общий множитель х(х+10)
210(х+10)=210х+0,5х(х+10)
0,5х^2+5х=2100 или х^2+10х=4200, х=60 км/ч

Answer 2

Calculation of Train Speed

To determine the speed at which the train was traveling before it stopped, we can use the information provided. Here are the steps to calculate the speed:

1. The total distance between the stations is given as 420 km. 2. When the train reached the halfway point, it was delayed for 30 minutes at a traffic light. 3. To make up for the delay, the train increased its speed by 10 km/h.

To calculate the speed of the train before it stopped, we need to find the time it took for the train to reach the halfway point.

Let's calculate the time it took for the train to reach the halfway point:

1. The total distance between the stations is 420 km, so the halfway point is at 210 km. 2. The train was delayed for 30 minutes at the halfway point.

To calculate the time it took for the train to reach the halfway point, we can use the formula:

Time = Distance / Speed

Let's calculate the time:

Time = 210 km / Speed

Since the train was delayed for 30 minutes, the total time it took for the train to reach the halfway point is:

Total Time = Time + Delay Time

Let's substitute the values and solve for the speed:

Total Time = 210 km / Speed + 30 minutes

Now, let's calculate the speed of the train before it stopped:

Speed = 210 km / (Total Time - 30 minutes)

Please note that we do not have the exact values for the total time and delay time, so we cannot provide an exact speed calculation. However, you can use the formula provided above to calculate the speed once you have the specific values for the total time and delay time.