DRDO Multi tasking staff Model paper 9

Initial speed = 10 km/h
Total time taken in the journey = [20/10] + [20/20] + [20/30] + [20/40] + [20/50] + [20/60]
= 2 + 1 + (2/3) + 0.5 + 0.4 + (1/3)
= 4.9 hours
∴ Average speed = 120/4.9 = 24.49 km/h (Approximately)
Thus, the correct answer is option 2.