Answer (D)
sound and speed of jeep coming from two different direction
speed of sound 330m/sec
speed of jeep is x m/sec (say)
Acc. the question if sound travel alone towards the man then he heard firing between 24 sec.
But as jeep also travel that time , (speed of jeep +speed of sound) takes 22 sec
(330+x) * 22 = 330*24
then, x=30m/sec