Find the Average Speed for the Whole Journey
Answer: (2) 7 km / hr.
A man completed 30 km of a journey at 6 km/h.
Then, time taken by a man to complete 30 km = 30 / 6
= 5 hr.
The remaining 40 km of the journey in 5 hours.
Then, time taken by a man to complete 40 km = 5 hr.
Average speed of a man = Total distance covered by a man / Total time taken by a man to cover the total distance.
Then, The average speed of a man = (30 + 40) /(5 + 5)
= 70 / 10
= 7 km / hr
Then, the average speed of a man is 7 km / hr.
Hence, the answer is (2) 7 km/hr.