Answer
The answer is below.
Work Step by Step
a) Since the intensity is inversely related to the square of the distance, it follows that if the distance is doubled, the intensity is 1/4 as much.
b) We use the equation for the decibel level:
$ \beta = 10log{(1/4)}\\ \beta = -6 $
Thus, the decibel level is decreased by 6 decibels.
