Question

Человек шел из деревни в город со скоростью 3 км/ч . Обратно он возвращался с покупками и шел со скорость 2 км/ч . Найти среднюю скорость на всем пути

Answer 1

средняя скорость=весь путь/все время в пути.

расстояния по условию равны(S₁=S₂),т.е.весь путьS=S₁+S₂=2S.

время в пути из деревни в город =S/3.время в пути назад a=S/2.

Все время в пути:  S  + S   =3S+2S  =    5S 

                                 3      2    6           6

Подставляем в формулу,имеем:

   2S    = 2S*6 =12/5=2,4(км/ч)-средняя скорость человека

  5S          5S

     6

Answer 2

Calculation of Average Speed

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

Let's assume the distance from the village to the city is D kilometers.

The person traveled from the village to the city with a speed of 3 km/h. The time taken for this part of the journey can be calculated using the formula:

Time taken = Distance / Speed

So, the time taken from the village to the city is D / 3 hours.

On the return journey, the person was carrying purchases and walked with a speed of 2 km/h. The time taken for this part of the journey can be calculated using the same formula:

Time taken = Distance / Speed

So, the time taken from the city back to the village is also D / 2 hours.

To find the total time taken for the entire journey, we add the time taken for the forward and return journeys:

Total time taken = (D / 3) + (D / 2) hours.

Now, to find the average speed, we divide the total distance traveled by the total time taken:

Average speed = Total distance / Total time taken

Since the person traveled the same distance from the village to the city and back, the total distance traveled is 2D kilometers.

Substituting the values, we get:

Average speed = 2D / [(D / 3) + (D / 2)]

Simplifying the expression, we get:

Average speed = 2D / [(2D + 3D) / 6]

Average speed = 2D / (5D / 6)

Average speed = 12D / 5D

Average speed = 12 / 5 km/h

Therefore, the average speed for the entire journey is 2.4 km/h.

Please note that the above calculation assumes a constant speed throughout the journey and does not take into account any breaks or variations in speed.