Resposta :
[tex]\begin{gathered}\LARGE\boxed{\begin{array}{lr}\rm \Large \text {$V = \lambda \cdot f$}\\\rm \Large \text {$V = 6 \cdot 10$}\\\rm\underline{\red{\boxed {\boxed {\Large \text{$\sf \Large \text {$V = 60$} \left[m/s\right] $}}}}}\end{array}}\end{gathered}[/tex]