Answer:
0.5 m/s
Explanation:
Here are some key formulae:
f=1/T
c=fλ
f=frequency
T=time period = 4
c= wavespeed (sometimes labelled as v)
λ=wavelength (lambda is the name of the symbol) = 2
I've also written in the values we know from the question.
(If you want more of an explanation, let me know)
1/T=f
so 1/4 = frequency
c=fλ
1/4 x 2 = 2/4 = 1/2 = 0.5
Don't forget units! (ms^(-1))
So your final answer is 0.5 m/s
Hope this Helps :)