Note that the units cancel such that Watts, a unit of power, are the units in the final answer.
A truck positioned 5m from an open window and a truck positioned 25m from an open window obviously create different sound intensities and power at the open window. This difference is reflected in the measurement of the intensity or the power. Since the measurement of sound level was given in the problem, the distance from the window was not necessary. Calculating the power based on distance from a detector is beyond the scope of this material.
