6 meters because it’s asking you to find the wavelength. The formula is velocity= frequency•wavelength, but in this case,since it’s asking for wavelength, it’s wavelength= velocity/frequency. 42 divided by 7 is 6. The final answer would be 6 meters. It’s not 6 seconds because wavelength doesn’t have that unit. The correct unit for wavelength is m. IN CONCLUSION....the answer is 6 meters