Question

Решите задачу по действиям с пояснениями: От вокзала до аэропорта отправился автобус со скоростью 69 км в час. Через 20 мин до аэропорта ему осталось проехать 107 км. Сколько времени понадобится автобусу на обратный путь, если он уменьшит скорость на 4 км в час?

Answer 1

69км×(1/3)ч=23км он проехал, значит расстояние равно 130 км
69-4=65 - уменьшенном скорость
130/65=2 ч

Answer 2

Problem Analysis

To solve this problem, we need to find the time it will take for the bus to travel back from the airport to the train station at a reduced speed after reaching the airport.

Given Data

- Initial speed of the bus: 69 km/h - Distance remaining to the airport after 20 minutes: 107 km - Reduced speed for the return journey: 4 km/h less than the initial speed

Solution Steps

1. Calculate the time taken to cover the remaining distance to the airport. 2. Use the time calculated in step 1 to find the total time taken for the return journey at the reduced speed.

Solution

1. Calculate the time taken to cover the remaining distance to the airport: - The time taken to cover the remaining distance to the airport can be calculated using the formula: \[ \text{Time} = \frac{\text{Distance}}{\text{Speed}} \] - Substituting the given values: \[ \text{Time} = \frac{107 \, \text{km}}{69 \, \text{km/h}} \] \[ \text{Time} \approx 1.55 \, \text{hours} \] 2. Calculate the total time taken for the return journey at the reduced speed: - Since the bus will travel at a reduced speed, the total time for the return journey can be calculated using the formula: \[ \text{Total Time} = \frac{\text{Distance}}{\text{Reduced Speed}} \] - Substituting the given values: \[ \text{Total Time} = \frac{107 \, \text{km}}{69 \, \text{km/h} - 4 \, \text{km/h}} \] \[ \text{Total Time} \approx 1.64 \, \text{hours} \]

Conclusion

The bus will need approximately 1.64 hours for the return journey at the reduced speed.