Engineering Physics

The volume of a room is $980,\mathrm{m^3}$. The wall area of the room is $150,\mathrm{m^2}$, ceiling area $95,\mathrm{m^2}$ and floor area is $90,\mathrm{m^2}$. The average sound absorption coefficient for wall is $0.03$, for ceiling is $0.80$ and for the floor is $0.06$. Calculate the average sound absorption coefficient and reverberation time for hall.