Path difference of the two sound waves x = 45.9 m - 34.7m
                                                               =
11.2 m
speed of sound v = 343 m/s
the lowest frequency that can be heard loudly due toconstructive
interference f = v / x
                                                                                                                       =30.7
Hz
Since for constructive interference path difference isintegral
multiple of wavelength
