a man walks on a straight road from his home to a market 2.5 km away with a speed of 5 km/h .

Time required to reach market = 2.5/5 = 0.5 hr = 30 min

Time required to reach home from market = 2.5/7.5 = 0.33 hr = 20 min. 

Magnitude Average Velocity (0 to 30 min) = net displacement/time = (final position - initial position)/time =

(market - home)/time = 2.5/0.5 = 5 km/hr

Magnitude Average Velocity (0 to 50 min) = net displacement/time = (final position - initial position)/time =

(home - home)/time = 0

Average speed (0 to 30 min) = total distance/total time = 2.5 km/ 0.5hr = 5 km/hr.

Average speed (0 to 50 min) = total distance/total time = (2.5 + 2.5)/(0.5 + 0.33) = 6 km/hr.

Regards,

Team,

TopperLearning.