Answer:
Average speed = 26.67 km/h
Step-by-step explanation:
It is given that,
The first half of the journey by a body is traveled with a speed of 40 km/h and the next half is covered with a speed of 20 km/h
We need to find the average speed of the whole journey. When two speeds are given, the average speed is given by :

So, the average speed of the body of the whole journey is 26.67 km/h.