Question

за первые 0,5 часов велосипедист преодолел 10км следуешие 12 минут он ехал со скоростью 25 км в час остольные 9 со скоростью 18 км в час какова средняя скорость велосипедиста на протяжении всего пути в первой половине пути

Answer 1

1 участок: s = 10 км, t = 0.5 ч

2 участок: s = vt, t = 0.2 ч 

  s = 25*0.2=5 км 

3 участок: s = 9 км, t = s/v

  t = 9/18 = 0.5

Средняя скорость равна отношению всего пути на все время

s = 10+5+9=24 км

t = 0.5+0.2+0.5 = 1.2 ч

vсредняя = 24/1.2 = 20 км/ч

Answer 2

Calculation of Average Speed

To calculate the average speed of the cyclist during the first half of the journey, we need to determine the total distance traveled and the total time taken.

According to the information provided, the cyclist covered 10 km in the first 0.5 hours (30 minutes) and then continued for another 12 minutes at a speed of 25 km/h. After that, the cyclist traveled the remaining 9 km at a speed of 18 km/h.

Let's break down the calculation step by step:

1. Convert the time taken for the first half of the journey to hours: - 0.5 hours + 12 minutes = 0.5 hours + (12/60) hours = 0.5 + 0.2 = 0.7 hours

2. Calculate the total distance traveled in the first half of the journey: - 10 km

3. Calculate the time taken for the second half of the journey: - 9 km / 18 km/h = 0.5 hours

4. Calculate the total distance traveled: - 10 km + 9 km = 19 km

5. Calculate the total time taken: - 0.7 hours + 0.5 hours = 1.2 hours

6. Calculate the average speed: - Average speed = Total distance / Total time - Average speed = 19 km / 1.2 hours = 15.83 km/h

Therefore, the average speed of the cyclist during the first half of the journey is approximately 15.83 km/h.