Answer:
[tex]6\:\mathrm{m/s}[/tex]
Explanation:
Denote average speed by [tex]S=\frac{d}{t}[/tex] where [tex]d[/tex] is total distance travelled and [tex]t[/tex] is time.
Plugging in given values, we get:
[tex]S=\frac{30}{5}=\fbox{$6\:\mathrm{m/s}$}[/tex].