A traveling wave is moving on a long cord in the +x direction. The wave function that describes this wave is given by:

y(x,t) = A sin(kx - wt + )

with amplitude = 25.0 cm, wavelength = 10.0 cm and phase constant = -/5. Determine the wave speed if its displacement at position x = 1.0 cm and time t = 0.50 s is -12.5 cm. Give answer in cm/s to three places to the right of the decimal.