Question

Первую часть пути самолёт пролетел за 40 мин со скоростью 12 км/мин.Затем он увеличел свою скорость на 14км/мин и приземлился ещё через 40мин.Какова была средняя скорость на всём пути?

Answer 1

12×40=480 км пролетел в первые 40 минут
14×40=560 км пролетел в следующие 40 минут
480+560=1040 км весь путь
40+40=80 мин все время пути
1040÷80=13 км/мин средняя скорость самолета

Answer 2

Calculation of Average Speed

To calculate the average speed for the entire journey, we need to find the total distance traveled and the total time taken.

Let's break down the information given:

- The first part of the journey lasted 40 minutes and the plane traveled at a speed of 12 km/min. - The second part of the journey also lasted 40 minutes, during which the plane increased its speed by 14 km/min.

To find the total distance traveled, we can calculate the distance covered in each part of the journey and then add them together.

1. Distance covered in the first part of the journey: - Time: 40 minutes - Speed: 12 km/min - Distance = Speed * Time = 12 km/min * 40 min = 480 km

2. Distance covered in the second part of the journey: - Time: 40 minutes - Speed: 12 km/min + 14 km/min = 26 km/min (after increasing the speed) - Distance = Speed * Time = 26 km/min * 40 min = 1040 km

Now, let's calculate the total distance traveled: - Total distance = Distance in the first part + Distance in the second part = 480 km + 1040 km = 1520 km

To find the total time taken for the entire journey, we add the time taken for each part of the journey:

- Total time = Time for the first part + Time for the second part = 40 min + 40 min = 80 min

Finally, we can calculate the average speed using the formula:

Average Speed = Total Distance / Total Time

Substituting the values we found:

Average Speed = 1520 km / 80 min

To convert the average speed to km/min, we divide the average speed by 60:

Average Speed = (1520 km / 80 min) / 60 = 19 km/min

Therefore, the average speed for the entire journey is 19 km/min.