Sound Waves

Name the sounds of the frequencies given below:
A point sound source is situated in a medium of bulk modulus $$1.6\,\times\,10^5\,N/m^2$$. An observer standing at a distance 10 m from the source writes down the equation for the wave as $$y\,=\,A\,sin\,(15\,\pi\,x\,-\,6000\,\pi\,t)$$ Here y and x are in meters and t is in second. The maximum pressure amplitude received to the the observer's ear is $$24\,\pi$$ Pa, then find :
A point sound source is situated in a medium of bulk modulus $$1.6\,\times\,10^5\,N/m^2$$. An observer standing at a distance 10 m from the source writes down the equation for the wave as $$y\,=\,A\,sin\,(15\,\pi\,x\,-\,6000\,\pi\,t)$$ Here y and x are in meters and t is in second. The maximum pressure amplitude received to the the observer's ear is $$24\,\pi$$ Pa, then find :
In a stationary wave :
Two coherent point sound sources $$S_{1}$$ and $$S_{2}$$ are placed as shown in the figure. Both are emitting sound of frequency 165 Hz. $$S_{1}$$ is ahead of $$S_{2}$$ in phase by $$\pi -$$radian. (Speed of sound is 330 m/s)