Calculate the average speed of the car over the intervals "A", "B" and "C".

Speed over interval "A". The car travels 40km in 3.5 hours. So the speed is
40/3.5 = 11.43km/hr

Speed over interval "B". The car travels 15km in 3 hours. So the speed is
40/3.5 = 5km/hr

Speed over interval "C". The car travels 25km in 1.5 hours. So the speed is
40/3.5 = 11.43km/hr

What is the average speed of the car over the entire journey?

Average s peed over the entire journey. The car travels a total of 80km in 8 hours. So the speed is
8 0/8 = 10km/hr

Two cars 80km apart travel towards each other . They start their journey at the same time.

Calculate the average speed of both vehicles over the entire journey.

Car "A" travels a total of 80 km in 8 hours. So the average speed is 80/8 =10km/hr

Car "B" travels a total of 80 km in 6 hours.

So the average speed is 80/6 =13.33km/hr