Question

Машина прошла расстояние в 510км. Она шла 2ч со скоростью 120км\ч, а остальной путь со скоростью 90км\ч. Сколько времени находилась машина в пути, если она сделала две остановки по 30мин.? Сможет ли машина пройти это расстояние за 6ч,если будет двигаться без остановок со скоростью 90км\ч.?

Answer 1

120 км/час*2 час=240 км (прошла со скоростью 120 км/час)
510 км-240 км=270 км (прошла со скоростью 90 км/час)
270 км: 90 км/час=3 часа (шла со скоростью 90 км/час)
30 мин+30 мин=1 час (время остановок)
2 часа+3 часа+1 час=6 часов (в пути с остановками)

510 км:90 км/час=5 60/90 часа=5 2/3 часа (будет идти со скоростью 90 км/час)
6 час - 5 2/3 часа = 1/3 часа (20 мин)

Ответ: - машина находилась в пути 6 часов с остановками.
            - машина пройдет расстояние в 510 км со скоростью 90 км/час за 5 2/3 часа (5 часов 40 минут), то есть на 20 минут быстрее 6 часов

Answer 2

Calculation of the Total Time and Possibility of Completing the Distance in 6 Hours

To calculate the total time the car was in motion, we need to consider the time it took to cover the distance at different speeds and the time spent on two 30-minute stops.

The car traveled a distance of 510 km. It traveled at a speed of 120 km/h for 2 hours and at a speed of 90 km/h for the remaining distance.

To calculate the time spent at each speed, we can use the formula:

Time = Distance / Speed

For the first part of the journey, the car traveled at a speed of 120 km/h for 2 hours, covering a distance of:

Distance = Speed * Time = 120 km/h * 2 hours = 240 km

For the second part of the journey, the car traveled at a speed of 90 km/h. To find the time, we can use the formula:

Time = Distance / Speed = (Total Distance - Distance Covered in the First Part) / Speed

Time = (510 km - 240 km) / 90 km/h = 270 km / 90 km/h = 3 hours

Therefore, the total time the car was in motion is:

Total Time = Time for the First Part + Time for the Second Part = 2 hours + 3 hours = 5 hours

Now, let's consider the two 30-minute stops. Each stop lasted for 30 minutes, so the total time spent on stops is:

Total Time on Stops = 2 stops * 30 minutes/stop = 60 minutes = 1 hour

Therefore, the total time the car was in motion, including the stops, is:

Total Time with Stops = Total Time + Total Time on Stops = 5 hours + 1 hour = 6 hours

Now, let's address the second part of the question: Can the car complete the distance of 510 km in 6 hours if it travels at a constant speed of 90 km/h without any stops?

Since the total time with stops is already 6 hours, it means that the car would not have any time left to complete the journey within 6 hours if it travels at a constant speed of 90 km/h. The car would need additional time to cover the remaining distance.

Therefore, it is not possible for the car to complete the distance of 510 km in 6 hours if it travels at a constant speed of 90 km/h without any stops.

Please let me know if you need any further clarification or assistance!