Question

На первом участке пути поезд шел 2ч со скостью 60км/ч,а на втором он шел 3ч.С какой скоростью шел поезд на втором участке,если его средняя скорость на двух участках была равна 51км/ч.

Answer 1

2+3=5(ч)-время за которое прошел поезд весь путь

5 *51=255(км)-весь путь

2 *60=120(км)-1участок пути

255-120=135(км)-2 участок пути

135:3=45(км/ч)-скорость поезда на 2 участке пути

Ответ: 45 км/ч скорость поезда на 2 участке пути.

Answer 2

Problem Analysis

We are given that a train traveled for 2 hours at a speed of 60 km/h on the first part of its journey, and then traveled for 3 hours on the second part. We need to find the speed at which the train traveled on the second part, given that its average speed for the entire journey was 51 km/h.

Solution

To solve this problem, we can use the formula for average speed:

Average Speed = Total Distance / Total Time

Let's assume the speed of the train on the second part of the journey is x km/h.

We can calculate the total distance traveled on the first part of the journey using the formula:

Distance = Speed × Time

For the first part of the journey, the distance is given by:

Distance1 = 60 km/h × 2 hours

For the second part of the journey, the distance is given by:

Distance2 = x km/h × 3 hours

The total distance for the entire journey is the sum of the distances for the two parts:

Total Distance = Distance1 + Distance2

The total time for the entire journey is the sum of the times for the two parts:

Total Time = 2 hours + 3 hours

Now we can substitute these values into the formula for average speed:

51 km/h = (Distance1 + Distance2) / (2 hours + 3 hours)

Simplifying the equation:

51 km/h = (120 km + 3x km) / 5 hours

To solve for x, we can cross-multiply and solve the resulting equation:

51 km/h × 5 hours = 120 km + 3x km

255 km = 120 km + 3x km

255 km - 120 km = 3x km

135 km = 3x km

Dividing both sides by 3:

45 km/h = x

Therefore, the train traveled at a speed of 45 km/h on the second part of the journey.

Answer

The train traveled at a speed of 45 km/h on the second part of the journey.