Two loudspeakers in the drawing are producing identical sound
waves. The waves spread out and overlap at the point P.
This situation is analogous to Young’s double-slit experiment,
except that sound waves are being used. What is the difference
ℓ₂ − ℓ₁ in the two path lengths if point
P is at the third sound intensity minimum from the central
sound intensity maximum? Express this difference in terms of the
wavelength λ of the sound.

Please show work!