Answer:
The distance d from the car at which the sound from the stereo can still be discerned = 97720.5 m
Explanation:
Sound intensity heard at distance is related to the distance with the relation = (power of sound at the source)/(surface area of the wall of an imaginary sphere at the distance in question)
I = P/4πd²
Assuming the car has 2 speakers,
P = 0.06 W × 2 = 0.12 W
d = ?
For the intensity of the least discernible sound,
I = 10⁻¹² W/m²
10⁻¹² = 0.12/4πd²
d = 97720.5 m