Question

Расстояние от Москвы до Владивостока-9000 километров. Первую треть пути поезд едет со скоростью 100км/ч, вторую в 2 раза медленнее, а третью часть пути со скоростью равной половине от суммы скоростей первой и второй частей пути. Сколько времени занимает путь от Москвы до Владивостока ?

Answer 1

9000:3=3000
3000:100=30ч
100:2=50
3000:50=60
3000:75=40
60+30+40=130ч

Answer 2

Calculating the Time Taken for the Journey from Moscow to Vladivostok

To calculate the time taken for the journey from Moscow to Vladivostok, we can break down the distance into three parts and calculate the time taken for each part separately.

1. Distance and Speed for Each Part: - The total distance from Moscow to Vladivostok is 9000 kilometers. - The train travels the first third of the distance at a speed of 100 km/h. - The second third of the distance is covered at a speed that is twice as slow as the first part. - The final third of the distance is covered at a speed equal to half the sum of the speeds of the first and second parts.

2. Calculating Time for Each Part: - Let's denote the time taken for the first, second, and third parts as t1, t2, and t3 respectively. - We can use the formula: time = distance / speed to calculate the time taken for each part.

3. Calculating Total Time: - The total time taken for the journey will be the sum of the times taken for each part.

Calculation

1. Time for the First Part: - Time taken for the first part, t1 = distance / speed = 9000 km / 100 km/h = 90 hours.

2. Time for the Second Part: - Speed for the second part = 100 km/h / 2 = 50 km/h. - Time taken for the second part, t2 = distance / speed = 9000 km / 50 km/h = 180 hours.

3. Time for the Third Part: - Speed for the third part = (100 km/h + 50 km/h) / 2 = 75 km/h. - Time taken for the third part, t3 = distance / speed = 9000 km / 75 km/h = 120 hours.

4. Total Time Taken: - Total time taken = t1 + t2 + t3 = 90 hours + 180 hours + 120 hours = 390 hours.

Conclusion

The journey from Moscow to Vladivostok, considering the varying speeds for different parts of the journey, takes approximately 390 hours.