A truck blowing horn of frequency 500 Hz travels towards a vertical mountain and driver hears echo …

Q: A truck blowing horn of frequency 500 Hz travels towards a vertical mountain and driver hears echo of frequency 600Hz. If velocity of sound in air is 340m/s then speed of truck is

(a) 31 m/s

(b) 41 m/s

(c) 51 m/s

(d) 21 m/s

Ans: (a)