Answer:
Average speed will be 48.23 km/h
Explanation:
Let the distance up to hill is = d km
Speed when car goes to hill = 38 km/h
So time required [tex]t=\frac{distance}{speed}=\frac{d}{38}hour[/tex]
Speed when car return from hill = 66 km/h
So time required to return fro hill [tex]t=\frac{d}{66}h[/tex]
Total time [tex]t_{total}=\frac{t}{38}+\frac{t}{66}[/tex]
Total distance = d+d =2d
So average speed[tex]=\frac{total\ distance}{total\ time}=\frac{2d}{\frac{d}{38}+\frac{d}{66}}=48.23km/h[/tex]
