Given: y = 15 sin \(\frac{2\pi}{5}\) (60t - x).

comparing  y = 15 sin \(\frac{2\pi}{5}\) (60t - x) with the equation of wave motion Asin\(\frac{2\pi}{\lambda}\)(x - vt)

\(\frac{2\pi}{5}\) = \(\frac{2\pi}{\lambda}\)

Therefore, \(\lambda\) = 5m.