Final answer:
The phase difference between two in-phase sound sources at a certain point depends on the path difference and can be calculated using the distances from the sources to the point and the speed of sound.
Step-by-step explanation:
The question concerns the phase difference between two point sources that are in phase and emitting sound waves of a certain frequency. Specifically, it looks at the phase difference that arises when the sound waves travel different distances to reach a certain point.
The phase difference depends on the path difference, which can be calculated using the speed of sound and the distances from the sources to the point in question. To determine the phase difference, one would need to know the exact distances mentioned in the question as well as the frequency of the sound wave to compute the number of wavelengths in the path difference.