Question

От дома до озера рыбак ехал 20 мин на велосипеде со скоростью 15 км/ч, потом 5 мин отдыхал, и ещё 25 мин шёл пешком со скоростью 6 км/ч. С какой средней скоростью он преодолел этот путь? Ответ выразить в км/ч, округлив до десятых.

Answer 1

15/3 + 0 + 6/60*25 равно 5+0+2,5, то есть 7,5 км. Всего было затрачено 50 минут. Составляем пропорцию. 7,5 км за 50 минут, а сколько км за 60 минут? Получаем 9 км/ч...

Answer 2

Calculation of Average Speed

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

The fisherman traveled for 20 minutes on a bicycle at a speed of 15 km/h, rested for 5 minutes, and then walked for 25 minutes at a speed of 6 km/h.

Let's calculate the total distance traveled:

- Distance traveled on the bicycle: 20 minutes * (15 km/h) = 5 km - Distance traveled on foot: 25 minutes * (6 km/h) = 2.5 km

The total distance traveled is 5 km + 2.5 km = 7.5 km.

Now, let's calculate the total time taken:

- Time taken on the bicycle: 20 minutes - Time taken on foot: 25 minutes

The total time taken is 20 minutes + 25 minutes = 45 minutes.

To find the average speed, we divide the total distance by the total time:

Average speed = Total distance / Total time

Average speed = 7.5 km / 45 minutes

To express the answer in km/h, we need to convert minutes to hours:

1 hour = 60 minutes

Average speed = 7.5 km / (45 minutes / 60 minutes per hour)

Average speed = 7.5 km / (0.75 hours)

Average speed = 10 km/h

Therefore, the fisherman's average speed for the entire journey, including both cycling and walking, is 10 km/h.