We have the next information
[tex]v=\frac{\lambda}{T}[/tex]Where
[tex]\lambda=6.69m=wave\text{ lenght}[/tex][tex]T=6.99\text{ sec}=\text{period}[/tex]we substitute the values
[tex]v=\frac{6.69}{6.99}=0.95\text{ m/s}[/tex]The speed of the wave is 0.95m/s
