Average speed of the entire journey is 3.08 km/hr
Explanation:
- Step 1: In the first half, given that the speed = 4 km/h and time = 2 1/2 = 2.5 hrs. Calculate the distance covered.
Distance = Speed × Time = 4 × 2.5 = 10 km
- Step 2: In the second half, given that speed = 2 1/2 = 2.5 km/hr and time = 4 hrs. Calculate the distance covered.
Distance = 2.5 × 4 = 10 km
- Step 3: Calculate average speed.
Average Speed = Total distance/Total time
= 10 + 10/2.5 + 4 = 20/6.5
= 3.08 km/hr