Average speed is defined as the ratio of total distance covered in total given time
[tex]speed = \frac{distance}{time}[/tex]
here we know that total distance that man moved is
[tex]d_1 = 200 km[/tex]
[tex]d_2 = 100 km[/tex]
so total distance is
[tex]d = d_1 + d_2[/tex]
[tex]d = 200 km + 100 km[/tex]
[tex]d = 300 km[/tex]
now here total time of the motion is
[tex]t_1 = 6 hours[/tex]
[tex]t_2 = 4 hours[/tex]
total time will be given as
[tex]t = t_1 + t_2 [/tex]
[tex]t = 6 + 4 = 10 hours[/tex]
now by above formula
[tex]v_{avg} = \frac{300}{10}[/tex]
[tex]v_{avg} = 30 km/h[/tex]
so his average speed is 30 km/h
