An automobile travels 72 km/hr towards a high wall. The driver sounds a horn of frequency 124 cycle/sec. What is the frequency of the reflected sound heard by the driver? (Velocity of sound = 330 m/sec)

An automobile travels 72 km/hr towards a high wall. The driver sounds

1.	An automobile travels 72 km/hr towards a high wall. The driver sounds a horn of frequency 124 cycle/sec. What is the frequency of the reflected sound heard by the driver? (Velocity of sound = 330 m/sec)
A.	124 cycles /sec
B.	132 cycles/sec
C.	140 cycles /sec
D.	148 cycles/sec
Answer» D. 148 cycles/sec