Physics - How much sound power is this speaker putting out?

Question

The sound level at a distance of 3.0 m from a loudspeaker is 95 dB. How much sound power is the speaker putting out? Assume this same sound level exists in all directions from the speaker.

Answer 1

120 dB is 1 Watt per square meter.  Every ten dB divides the intensity by 10 (and 5dB by the square root of ten).  So find the intensity in Watts/m² from 95dB, and then multiply by the area of a sphere of radius 3m.