Question

A car drives 10km with a speed of 72 km/hr and then runs out of gas. Then you walk 2km for the next 30 min

Answer 1

Given :

A car drives 10 km with a speed of 72 km/hr and then runs out of gas.

Then you walk 2 km for the next 30 min  until you find a gas station .

To Find :

The average speed of whole journey .

Solution :

Average speed is given by :

$v_{avg}=\dfrac{\text{Total distance covered}}{\text{Total time taken}}\\\\v_{avg}=\dfrac{10+2}{\dfrac{10}{72}+\dfrac{1}{2}}\\\\\\v_{avg}=18.78\ km/hr$

Hence , this is the required solution .