A stationary source is emitting sound at a fixed frequency ` f_(0)` which is reflected by two cars approaching the source . The difference between the frequencies of sound reflected from the cars is ` 1.2% ` of ` f_(0) ` . What is the differernce in the speeds of the cars ( in km per hour) to nearest interger ? The cars are moving at constant speeds much smaller then the speed of sound which is 330 m ` s^(-1)` .

Answer

7