d = total displacement of the person running due east = 15 km
t = time taken by the person to travel the given distance due east = 2.0 hr
v = average velocity of the person in east direction = ?
average velocity is the ratio of total displacement to total time taken. hence
average velocity = total displacement/total time
v = d/t
inserting the values
v = 15 km/2.0 hr
v = 7.50 km/hr
