In a location where the speed of sound is 354 m/s, a 2 000-Hz sound wave impinges

Question:

In a location where the speed of sound is 354 m/s, a 2 000-Hz sound wave impinges on two slits 30.0 cm apart.
(a) At what angle is the first maximum located?
(b) If the sound wave is replaced by 3.00-cm microwaves, what slit separation gives the same angle for the first maximum?
(c) If the slit separation is 1.00 µm, what frequency of light gives the same first maximum angle?