Remember that sound intensity decreases in inverse proportion to the distance squared. So, to solve this we are going to use the inverse square formula: 
where
is the intensity at distance 2
is the intensity at distance 1
is distance 2
is distance 1
We can infer for our problem that
, 
, and 
. Lets replace those values in our formula to find :
dB
We can conclude that the intensity of the sound when is <span>3 m from the source is 30 dB.</span>
where
We can infer for our problem that
We can conclude that the intensity of the sound when is <span>3 m from the source is 30 dB.</span>