$A$ sound source is moving towards a stationary listener with $1/10$th of the speed of sound. The ratio of apparent to real frequency is

$A$ police car with a siren of frequency $8 \ kHz$ is moving with uniform velocity $36 \ km/h$ towards a tall building which reflects the sound waves. The speed of sound in air is $320 \ m/s$. The frequency of the siren heard by the car driver is (in $kHz$)

$A$ person observes two moving trains,$A$ reaching the station and $B$ leaving the station with equal speed of $30\,m/s$. If both trains emit sounds with frequency $300\,Hz$,(Speed of sound : $330\,m/s$) the approximate difference of frequencies heard by the person will be $..........Hz$.

$A$ musician on a moving vehicle plays a tone at $880 \ Hz$. When the vehicle is approaching a listener, the listener receives it as an $888 \ Hz$ tone. What is the speed of the vehicle (in $m \ s^{-1}$)? (Assume the velocity of sound is $333 \ m \ s^{-1}$)

At what speed should a source of sound move so that the observer finds the apparent frequency equal to half the original frequency?

$A$ source of sound is moving with a constant velocity of $20\, m/s$ emitting a note of frequency $1000\, Hz.$ The ratio of frequencies observed by a stationary observer while the source is approaching him and after it crosses him will be (Speed of sound $v = 340\, m/s$).