A factory alarm is fixed to an outer concrete wall 96m thick. Inside the factory, an open corridor runs parallel to the wall for 120m. When the alarm rings, a worker standing at the far end of the corridor can hear the sound arriving by two paths: directly through the concrete wall and through the air in the corridor. \newline
Given: speed of sound in concrete =3200m/s, speed of sound in air =340m/s, which statement is correct regarding the arrival times?
(a) Sound through concrete arrives first, about 0.03s before the sound through air
(b) Sound through air arrives first, about 0.25s before the sound through concrete
(c) Sound through concrete arrives first, about 0.30s before the sound through air
(d) Both paths deliver sound simultaneously