Can you please help me answer number 4?

4. A wall is connected to a mass of 6.0 kilograms by a string that passes over a massless, frictionless pulley, as shown. The string has a uniform mass of 0.327 kilogram and a length of 5.0 meters. A wave pulse traveling along the string has a wavelength of 0.25 meter. (a) Find the speed of a wave pulse traveling along the string. 6.0 kg (b) Find the frequency of a wave pulse traveling along the string