Question

Самолет пролетел первую половину пути со скоростью 900 км\ч, а оставшуюся со скоростью 700 км\ч.Найти среднюю скорость.

Answer 1

Решение на фото, успехов :)

Answer 2

Calculation of Average Speed

To find the average speed of the plane, we can use the formula:

Average Speed = Total Distance / Total Time

In this case, the plane traveled the first half of the distance at a speed of 900 km/h and the remaining half at a speed of 700 km/h. Since the distance is the same for both halves, we can assume that the total distance is twice the distance traveled in the first half.

Let's denote the distance traveled in the first half as d. Therefore, the total distance is 2d.

To calculate the total time, we need to find the time taken for each half of the distance and then add them together.

The time taken for the first half of the distance can be calculated using the formula:

Time = Distance / Speed

For the first half, the distance is d and the speed is 900 km/h. Therefore, the time taken for the first half is d / 900.

Similarly, the time taken for the second half of the distance can be calculated using the formula:

Time = Distance / Speed

For the second half, the distance is d and the speed is 700 km/h. Therefore, the time taken for the second half is d / 700.

Adding the times for both halves, we get the total time:

Total Time = (d / 900) + (d / 700)

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

Average Speed = Total Distance / Total Time

Average Speed = (2d) / [(d / 900) + (d / 700)]

Simplifying the expression, we get:

Average Speed = (2d * 900 * 700) / (900d + 700d)

Average Speed = (2 * 900 * 700) / (900 + 700)

Now, we can calculate the average speed using the given values.

Let's calculate it:

Average Speed = (2 * 900 * 700) / (900 + 700)

Average Speed = (2 * 900 * 700) / 1600

Average Speed = 1260000 / 1600

Average Speed = 787.5 km/h

Therefore, the average speed of the plane is 787.5 km/h.