Answer
0.142 s
Work Step by Step
The time for the sound to travel to the microphone is the same for both listeners and may be neglected.
Find the difference between the time for sound to travel in air to the balcony, and for an electromagnetic wave to travel 1200 km.
$$\Delta t=t_{air}-t_{EM}$$
$$=\frac{50.0m}{343m/s}-\frac{1.2\times10^6m}{3.00\times10^8m/s}=0.142s$$
It takes longer for sound to travel in air to the balcony.
The person at home hears the singer’s voice about 0.142 seconds sooner, assuming there are no other delays.
