A train moves towards a stationary observer with speed 34 m/s. The train sounds a whistle and its frequency registered by the observer is `f_(1)`. If the speed of train is reduced to 17 m/s, the frequency registered is `f_(2)`. If speed fo sound is 340 m/s, then the ratio `f_(1)//f_(2)` is :

Options

A. `(18)/(19)`
B. `(1)/(2)`
C. `2`
D. `(19)/(18)`

Answer

D

Explanation

`f_(1)=f[(V)/(V-v_(1))]`, `f_(2)=f[(V)/(V-v_(2))]`