ANSWER:
5.13 m/s
STEP-BY-STEP EXPLANATION:
First we calculate the total length, like this:
[tex]\begin{gathered} l=28\cdot11 \\ l=308 \end{gathered}[/tex]Now we divide by the time it takes, which is equal to 1 minute, that is 60 seconds, therefore:
[tex]\begin{gathered} v=\frac{308}{60} \\ v=5.13\text{ m/s} \end{gathered}[/tex]The speed of the wave is 5.13 m/s
