Question

Пешеход часть пути прошёл со скоростью 3 км/ч, затратив на это 2/3 времени своего движения. За оставшуюся треть времени он прошёл остальной путь со скоростью 6 км/ч. Определите среднюю скорость.

Answer 1

Υcp=st , где s = s1 + s2 ; s1 = Δr1 = υ1·t1 ; s2 = υ2·t2 ; t1 = 2/3t ; t2 = t - t1 = 1/3t ; υ1 = 3 км/ч; υ2 = 6 км/ч. Тогда
υcp=s1+s2t=υ1⋅t1+υ2⋅t2t=υ1⋅2t3+υ2⋅t3t=2υ1+υ23 ; υср = 4 км/ч.

Answer 2

Calculating the Average Speed of the Pedestrian

To calculate the average speed of the pedestrian, we can use the formula:

Average Speed = Total Distance / Total Time

First, let's calculate the total distance covered by the pedestrian.

The pedestrian covered the first part of the distance at a speed of 3 km/h, spending 2/3 of the total time on it, and the remaining distance at a speed of 6 km/h, spending 1/3 of the total time on it.

Let's denote: - \( d_1 \) as the distance covered at 3 km/h - \( t_1 \) as the time spent covering \( d_1 \) - \( d_2 \) as the distance covered at 6 km/h - \( t_2 \) as the time spent covering \( d_2 \)

We can use the formula: \[ t_1 = \frac{2}{3} \times \text{Total Time} \] \[ t_2 = \frac{1}{3} \times \text{Total Time} \]

The total distance can be calculated as: \[ \text{Total Distance} = d_1 + d_2 \]

Now, let's calculate the total time taken: \[ \text{Total Time} = t_1 + t_2 \]

Finally, we can calculate the average speed using the formula: \[ \text{Average Speed} = \frac{\text{Total Distance}}{\text{Total Time}} \]

Let's proceed with the calculations.