Two trains A and B are moving with speeds 20 m/s and 30 m/s respectively in the same direction on the same straight track, with B ahead of A. The engines are at the front ends. The engine of train A blows a long whistle.Assume that the sound of the whistle is composed of components varying in frequency from f1=800 Hz to f2=1120 Hz as shown in the figure. The speed in the frequency (highest frequency lowest frequency) is thus 320 Hz. The speed of sound in still air is 340 m/s.The speed of sound of the whistle is :
![1011960_ee50f000e7e442129d83cf006cb6b80e.png](https://search-static.byjusweb.com/question-images/toppr_invalid/questions/1011960_ee50f000e7e442129d83cf006cb6b80e.png)