Question

путь от реки до железнодорожной станции,равный 8 км,проходил сначала по проселочной дороге,а затем по шоссе.На путь по проселочной дороге велосипедист затратил 40 минут,а по шоссе-20 минут.Выехав на шоссе велосипедист увеличил скорость в 2 раза.С какой скоростью велосипедист ехал по проселочной дороге?

Answer 1

Calculation of the Bicyclist's Speed on the Dirt Road

To find the speed at which the bicyclist traveled on the dirt road, we can use the formula:

Speed = Distance / Time

Given that the distance traveled on the dirt road is 8 km and the time taken is 40 minutes, we can substitute these values into the formula to find the speed.

Speed on the dirt road = 8 km / 40 min

To calculate the speed, we need to convert the time from minutes to hours since the distance is given in kilometers. There are 60 minutes in an hour, so we divide the time by 60.

Speed on the dirt road = 8 km / (40 min / 60 min/hour)

Simplifying the expression:

Speed on the dirt road = 8 km / (2/3 hour)

To divide by a fraction, we multiply by its reciprocal:

Speed on the dirt road = 8 km * (3/2 hour)

Multiplying the distance by the reciprocal of the time:

Speed on the dirt road = (8 km * 3) / 2 hour

Simplifying the expression:

Speed on the dirt road = 24 km / 2 hour

Finally, we can calculate the speed:

Speed on the dirt road = 12 km/h

Therefore, the bicyclist traveled at a speed of 12 km/h on the dirt road.