Answer:
The average speed of his journey is 4.8 kilometre per hour
Step-by-step explanation:
The given parameters are;
The distance from the man's home to the market = 3 km
The man's speed on his way to the market = 4 km/h
The man's speed on his way back to his home = 6 km/h
The average speed, s = The total distance, d divided by the time, t that elapsed during the journey
s = d/t
We note that time = Distance/Speed
The time it took the man to get to the market = Distance/Speed
The time it took the man to get to the market = 3 km/(4 km/hr) = 3/4 hours
The time it took the man to get to get back to his home = 3 km/(6 km/hr) = 1/2 hours
The total time to and from the market = 3/4 + 1/2 = 5/4 hours = 1.25 hours
The total distance covered by the man = 3 + 3 = 6 km
The average speed, s = 6 km/(1.25 hours) = 4.8 km/hr
The average speed of his journey = 4.8 km/hr.