If the dimension of the room is $10*8*6 m^3$

Given Data :- $V = 10×8×6=480m^3 $

$S = 2[(10×8)+(8×6)+(10×6)] = 376 m^3$

$ T = 3 sec.$

Formula :- $ T=0.161 V/A=0.161 V/(α_av.S)$

Calculations:- A= $ (0.161×V)/T= (0.161×480)/3= 25.76 sabine-m^2$

$α_av= A/S= 25.76/376= 0.068$ sabine.

Answer :-

Total absorption , A = 25.76 $ sabine-m^2$

Average absorption coefficient, $α_av = 0.068 sabine.$