Two guitars that are out of tune with each other play a note that has a wavelength of 64.51 cm on one guitar and 65.1 cm on the other guitar. What is the beat frequency (in Hz) heard by the two...

Two guitars that are out of tune with each other play a note that has a wavelength of 64.51 cm on one guitar and 65.1 cm on the other guitar. What is the beat frequency (in Hz) heard by the two guitarists when they play the notes together? Assume that the speed of sound is 344 m/s.