We know, Speed = Distance / time
Here, d = 30 m
t = 3 1/4 min = 13/4 min. = 13/4 * 60 = 195 sec
Substitute their value,
s = 30 / 195
s = 6/39 m/s
In short, Your Answer would be 6/39 or 0.153 m/s
[ Your Units might be different so be careful with that ]
Hope this helps!