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 form 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 observer’s ear is 24$\pi$  Pa, then the density of the medium is given by n kg/m³. Find n.