Answer:
Average speed of the cart will be 28.4745 km/hr
Step-by-step explanation:
Let the distance of the hill is d
Velocity of the cart when it is is pulled up to the hill is 24 km/hr
So time
![t=(d)/(24)hr](https://img.qammunity.org/2020/formulas/physics/high-school/xy2ealo3fp0vjjhsiy0lehphigt6udahk1.png)
Velocity of the cart when it is pulled down = 35 km/hr
So time taken
![t=(d)/(35)hr](https://img.qammunity.org/2020/formulas/physics/high-school/ce2bgl8yny1ie6hjbw6mh0afyedyit396j.png)
We know that average velocity is given by
![average\ velocity=(total\ distance)/(total\ time)=(2d)/((d)/(24)+(d)/(35))=28.4745kmn/hr](https://img.qammunity.org/2020/formulas/physics/high-school/9xj4n8l4ybuvrudiqs91douopissu6o8wm.png)