A man travels along a square path each side of length 100m with a velocity of 40m/s,50m/s 40m/s and 50m/s respectively calculate the average velocity

Answer 1

time = distance/speed, so the times along the sides are
100/40 and 100/50
avg speed is totaldistance/totaltime

But you want average velocity, which is zero, because the total displacement at the end is zero.